Uploaded Test files

venv/Lib/site-packages/traitlets/config/__init__.py

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+# encoding: utf-8
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+from .application import *
+from .configurable import *
+from .loader import Config

venv/Lib/site-packages/traitlets/config/application.py

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+# encoding: utf-8
+"""A base class for a configurable application."""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+from __future__ import print_function
+
+from copy import deepcopy
+import json
+import logging
+import os
+import re
+import sys
+from collections import defaultdict, OrderedDict
+
+from decorator import decorator
+
+from traitlets.config.configurable import Configurable, SingletonConfigurable
+from traitlets.config.loader import (
+    KVArgParseConfigLoader, PyFileConfigLoader, Config, ArgumentError, ConfigFileNotFound, JSONFileConfigLoader
+)
+
+from traitlets.traitlets import (
+    Bool, Unicode, List, Enum, Dict, Instance, TraitError, observe, observe_compat, default,
+)
+from ipython_genutils.importstring import import_item
+from ipython_genutils.text import indent, wrap_paragraphs, dedent
+from ipython_genutils import py3compat
+
+import six
+
+#-----------------------------------------------------------------------------
+# Descriptions for the various sections
+#-----------------------------------------------------------------------------
+
+# merge flags&aliases into options
+option_description = """
+Arguments that take values are actually convenience aliases to full
+Configurables, whose aliases are listed on the help line. For more information
+on full configurables, see '--help-all'.
+""".strip() # trim newlines of front and back
+
+keyvalue_description = """
+Parameters are set from command-line arguments of the form:
+`--Class.trait=value`.
+This line is evaluated in Python, so simple expressions are allowed, e.g.::
+`--C.a='range(3)'` For setting C.a=[0,1,2].
+""".strip() # trim newlines of front and back
+
+# sys.argv can be missing, for example when python is embedded. See the docs
+# for details: http://docs.python.org/2/c-api/intro.html#embedding-python
+if not hasattr(sys, "argv"):
+    sys.argv = [""]
+
+subcommand_description = """
+Subcommands are launched as `{app} cmd [args]`. For information on using
+subcommand 'cmd', do: `{app} cmd -h`.
+"""
+# get running program name
+
+#-----------------------------------------------------------------------------
+# Application class
+#-----------------------------------------------------------------------------
+
+
+
+_envvar = os.environ.get('TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR','')
+if _envvar.lower() in {'1','true'}:
+    TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR = True
+elif _envvar.lower() in {'0','false',''} :
+    TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR = False
+else:
+    raise ValueError("Unsupported value for environment variable: 'TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR' is set to '%s' which is none of  {'0', '1', 'false', 'true', ''}."% _envvar )
+
+
+@decorator
+def catch_config_error(method, app, *args, **kwargs):
+    """Method decorator for catching invalid config (Trait/ArgumentErrors) during init.
+
+    On a TraitError (generally caused by bad config), this will print the trait's
+    message, and exit the app.
+
+    For use on init methods, to prevent invoking excepthook on invalid input.
+    """
+    try:
+        return method(app, *args, **kwargs)
+    except (TraitError, ArgumentError) as e:
+        app.print_help()
+        app.log.fatal("Bad config encountered during initialization:")
+        app.log.fatal(str(e))
+        app.log.debug("Config at the time: %s", app.config)
+        app.exit(1)
+
+
+class ApplicationError(Exception):
+    pass
+
+
+class LevelFormatter(logging.Formatter):
+    """Formatter with additional `highlevel` record
+
+    This field is empty if log level is less than highlevel_limit,
+    otherwise it is formatted with self.highlevel_format.
+
+    Useful for adding 'WARNING' to warning messages,
+    without adding 'INFO' to info, etc.
+    """
+    highlevel_limit = logging.WARN
+    highlevel_format = " %(levelname)s |"
+
+    def format(self, record):
+        if record.levelno >= self.highlevel_limit:
+            record.highlevel = self.highlevel_format % record.__dict__
+        else:
+            record.highlevel = ""
+        return super(LevelFormatter, self).format(record)
+
+
+class Application(SingletonConfigurable):
+    """A singleton application with full configuration support."""
+
+    # The name of the application, will usually match the name of the command
+    # line application
+    name = Unicode(u'application')
+
+    # The description of the application that is printed at the beginning
+    # of the help.
+    description = Unicode(u'This is an application.')
+    # default section descriptions
+    option_description = Unicode(option_description)
+    keyvalue_description = Unicode(keyvalue_description)
+    subcommand_description = Unicode(subcommand_description)
+
+    python_config_loader_class = PyFileConfigLoader
+    json_config_loader_class = JSONFileConfigLoader
+
+    # The usage and example string that goes at the end of the help string.
+    examples = Unicode()
+
+    # A sequence of Configurable subclasses whose config=True attributes will
+    # be exposed at the command line.
+    classes = []
+
+    def _classes_inc_parents(self):
+        """Iterate through configurable classes, including configurable parents
+
+        Children should always be after parents, and each class should only be
+        yielded once.
+        """
+        seen = set()
+        for c in self.classes:
+            # We want to sort parents before children, so we reverse the MRO
+            for parent in reversed(c.mro()):
+                if issubclass(parent, Configurable) and (parent not in seen):
+                    seen.add(parent)
+                    yield parent
+
+    # The version string of this application.
+    version = Unicode(u'0.0')
+
+    # the argv used to initialize the application
+    argv = List()
+
+    # Whether failing to load config files should prevent startup
+    raise_config_file_errors = Bool(TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR)
+
+    # The log level for the application
+    log_level = Enum((0,10,20,30,40,50,'DEBUG','INFO','WARN','ERROR','CRITICAL'),
+                    default_value=logging.WARN,
+                    help="Set the log level by value or name.").tag(config=True)
+
+    @observe('log_level')
+    @observe_compat
+    def _log_level_changed(self, change):
+        """Adjust the log level when log_level is set."""
+        new = change.new
+        if isinstance(new, six.string_types):
+            new = getattr(logging, new)
+            self.log_level = new
+        self.log.setLevel(new)
+
+    _log_formatter_cls = LevelFormatter
+
+    log_datefmt = Unicode("%Y-%m-%d %H:%M:%S",
+        help="The date format used by logging formatters for %(asctime)s"
+    ).tag(config=True)
+
+    log_format = Unicode("[%(name)s]%(highlevel)s %(message)s",
+        help="The Logging format template",
+    ).tag(config=True)
+
+    @observe('log_datefmt', 'log_format')
+    @observe_compat
+    def _log_format_changed(self, change):
+        """Change the log formatter when log_format is set."""
+        _log_handler = self.log.handlers[0]
+        _log_formatter = self._log_formatter_cls(fmt=self.log_format, datefmt=self.log_datefmt)
+        _log_handler.setFormatter(_log_formatter)
+
+    @default('log')
+    def _log_default(self):
+        """Start logging for this application.
+
+        The default is to log to stderr using a StreamHandler, if no default
+        handler already exists.  The log level starts at logging.WARN, but this
+        can be adjusted by setting the ``log_level`` attribute.
+        """
+        log = logging.getLogger(self.__class__.__name__)
+        log.setLevel(self.log_level)
+        log.propagate = False
+        _log = log # copied from Logger.hasHandlers() (new in Python 3.2)
+        while _log:
+            if _log.handlers:
+                return log
+            if not _log.propagate:
+                break
+            else:
+                _log = _log.parent
+        if sys.executable and sys.executable.endswith('pythonw.exe'):
+            # this should really go to a file, but file-logging is only
+            # hooked up in parallel applications
+            _log_handler = logging.StreamHandler(open(os.devnull, 'w'))
+        else:
+            _log_handler = logging.StreamHandler()
+        _log_formatter = self._log_formatter_cls(fmt=self.log_format, datefmt=self.log_datefmt)
+        _log_handler.setFormatter(_log_formatter)
+        log.addHandler(_log_handler)
+        return log
+
+    # the alias map for configurables
+    aliases = Dict({'log-level' : 'Application.log_level'})
+
+    # flags for loading Configurables or store_const style flags
+    # flags are loaded from this dict by '--key' flags
+    # this must be a dict of two-tuples, the first element being the Config/dict
+    # and the second being the help string for the flag
+    flags = Dict()
+    @observe('flags')
+    @observe_compat
+    def _flags_changed(self, change):
+        """ensure flags dict is valid"""
+        new = change.new
+        for key, value in new.items():
+            assert len(value) == 2, "Bad flag: %r:%s" % (key, value)
+            assert isinstance(value[0], (dict, Config)), "Bad flag: %r:%s" % (key, value)
+            assert isinstance(value[1], six.string_types), "Bad flag: %r:%s" % (key, value)
+
+
+    # subcommands for launching other applications
+    # if this is not empty, this will be a parent Application
+    # this must be a dict of two-tuples,
+    # the first element being the application class/import string
+    # and the second being the help string for the subcommand
+    subcommands = Dict()
+    # parse_command_line will initialize a subapp, if requested
+    subapp = Instance('traitlets.config.application.Application', allow_none=True)
+
+    # extra command-line arguments that don't set config values
+    extra_args = List(Unicode())
+
+    cli_config = Instance(Config, (), {},
+        help="""The subset of our configuration that came from the command-line
+
+        We re-load this configuration after loading config files,
+        to ensure that it maintains highest priority.
+        """
+    )
+
+    _loaded_config_files = List()
+
+    def __init__(self, **kwargs):
+        SingletonConfigurable.__init__(self, **kwargs)
+        # Ensure my class is in self.classes, so my attributes appear in command line
+        # options and config files.
+        cls = self.__class__
+        if cls not in self.classes:
+            if self.classes is cls.classes:
+                # class attr, assign instead of insert
+                cls.classes = [cls] + self.classes
+            else:
+                self.classes.insert(0, self.__class__)
+
+    @observe('config')
+    @observe_compat
+    def _config_changed(self, change):
+        super(Application, self)._config_changed(change)
+        self.log.debug('Config changed:')
+        self.log.debug(repr(change.new))
+
+    @catch_config_error
+    def initialize(self, argv=None):
+        """Do the basic steps to configure me.
+
+        Override in subclasses.
+        """
+        self.parse_command_line(argv)
+
+
+    def start(self):
+        """Start the app mainloop.
+
+        Override in subclasses.
+        """
+        if self.subapp is not None:
+            return self.subapp.start()
+
+    def print_alias_help(self):
+        """Print the alias part of the help."""
+        if not self.aliases:
+            return
+
+        lines = []
+        classdict = {}
+        for cls in self.classes:
+            # include all parents (up to, but excluding Configurable) in available names
+            for c in cls.mro()[:-3]:
+                classdict[c.__name__] = c
+
+        for alias, longname in self.aliases.items():
+            classname, traitname = longname.split('.',1)
+            cls = classdict[classname]
+
+            trait = cls.class_traits(config=True)[traitname]
+            help = cls.class_get_trait_help(trait).splitlines()
+            # reformat first line
+            help[0] = help[0].replace(longname, alias) + ' (%s)'%longname
+            if len(alias) == 1:
+                help[0] = help[0].replace('--%s='%alias, '-%s '%alias)
+            lines.extend(help)
+        # lines.append('')
+        print(os.linesep.join(lines))
+
+    def print_flag_help(self):
+        """Print the flag part of the help."""
+        if not self.flags:
+            return
+
+        lines = []
+        for m, (cfg,help) in self.flags.items():
+            prefix = '--' if len(m) > 1 else '-'
+            lines.append(prefix+m)
+            lines.append(indent(dedent(help.strip())))
+        # lines.append('')
+        print(os.linesep.join(lines))
+
+    def print_options(self):
+        if not self.flags and not self.aliases:
+            return
+        lines = ['Options']
+        lines.append('-'*len(lines[0]))
+        lines.append('')
+        for p in wrap_paragraphs(self.option_description):
+            lines.append(p)
+            lines.append('')
+        print(os.linesep.join(lines))
+        self.print_flag_help()
+        self.print_alias_help()
+        print()
+
+    def print_subcommands(self):
+        """Print the subcommand part of the help."""
+        if not self.subcommands:
+            return
+
+        lines = ["Subcommands"]
+        lines.append('-'*len(lines[0]))
+        lines.append('')
+        for p in wrap_paragraphs(self.subcommand_description.format(
+                    app=self.name)):
+            lines.append(p)
+            lines.append('')
+        for subc, (cls, help) in self.subcommands.items():
+            lines.append(subc)
+            if help:
+                lines.append(indent(dedent(help.strip())))
+        lines.append('')
+        print(os.linesep.join(lines))
+
+    def print_help(self, classes=False):
+        """Print the help for each Configurable class in self.classes.
+
+        If classes=False (the default), only flags and aliases are printed.
+        """
+        self.print_description()
+        self.print_subcommands()
+        self.print_options()
+
+        if classes:
+            help_classes = self.classes
+            if help_classes:
+                print("Class parameters")
+                print("----------------")
+                print()
+                for p in wrap_paragraphs(self.keyvalue_description):
+                    print(p)
+                    print()
+
+            for cls in help_classes:
+                cls.class_print_help()
+                print()
+        else:
+            print("To see all available configurables, use `--help-all`")
+            print()
+
+        self.print_examples()
+
+    def document_config_options(self):
+        """Generate rST format documentation for the config options this application
+
+        Returns a multiline string.
+        """
+        return '\n'.join(c.class_config_rst_doc()
+                         for c in self._classes_inc_parents())
+
+
+    def print_description(self):
+        """Print the application description."""
+        for p in wrap_paragraphs(self.description):
+            print(p)
+            print()
+
+    def print_examples(self):
+        """Print usage and examples.
+
+        This usage string goes at the end of the command line help string
+        and should contain examples of the application's usage.
+        """
+        if self.examples:
+            print("Examples")
+            print("--------")
+            print()
+            print(indent(dedent(self.examples.strip())))
+            print()
+
+    def print_version(self):
+        """Print the version string."""
+        print(self.version)
+
+    @catch_config_error
+    def initialize_subcommand(self, subc, argv=None):
+        """Initialize a subcommand with argv."""
+        subapp,help = self.subcommands.get(subc)
+
+        if isinstance(subapp, six.string_types):
+            subapp = import_item(subapp)
+
+        # clear existing instances
+        self.__class__.clear_instance()
+        # instantiate
+        self.subapp = subapp.instance(parent=self)
+        # and initialize subapp
+        self.subapp.initialize(argv)
+
+    def flatten_flags(self):
+        """flatten flags and aliases, so cl-args override as expected.
+
+        This prevents issues such as an alias pointing to InteractiveShell,
+        but a config file setting the same trait in TerminalInteraciveShell
+        getting inappropriate priority over the command-line arg.
+
+        Only aliases with exactly one descendent in the class list
+        will be promoted.
+
+        """
+        # build a tree of classes in our list that inherit from a particular
+        # it will be a dict by parent classname of classes in our list
+        # that are descendents
+        mro_tree = defaultdict(list)
+        for cls in self.classes:
+            clsname = cls.__name__
+            for parent in cls.mro()[1:-3]:
+                # exclude cls itself and Configurable,HasTraits,object
+                mro_tree[parent.__name__].append(clsname)
+        # flatten aliases, which have the form:
+        # { 'alias' : 'Class.trait' }
+        aliases = {}
+        for alias, cls_trait in self.aliases.items():
+            cls,trait = cls_trait.split('.',1)
+            children = mro_tree[cls]
+            if len(children) == 1:
+                # exactly one descendent, promote alias
+                cls = children[0]
+            aliases[alias] = '.'.join([cls,trait])
+
+        # flatten flags, which are of the form:
+        # { 'key' : ({'Cls' : {'trait' : value}}, 'help')}
+        flags = {}
+        for key, (flagdict, help) in self.flags.items():
+            newflag = {}
+            for cls, subdict in flagdict.items():
+                children = mro_tree[cls]
+                # exactly one descendent, promote flag section
+                if len(children) == 1:
+                    cls = children[0]
+                newflag[cls] = subdict
+            flags[key] = (newflag, help)
+        return flags, aliases
+
+    @catch_config_error
+    def parse_command_line(self, argv=None):
+        """Parse the command line arguments."""
+        argv = sys.argv[1:] if argv is None else argv
+        self.argv = [ py3compat.cast_unicode(arg) for arg in argv ]
+
+        if argv and argv[0] == 'help':
+            # turn `ipython help notebook` into `ipython notebook -h`
+            argv = argv[1:] + ['-h']
+
+        if self.subcommands and len(argv) > 0:
+            # we have subcommands, and one may have been specified
+            subc, subargv = argv[0], argv[1:]
+            if re.match(r'^\w(\-?\w)*$', subc) and subc in self.subcommands:
+                # it's a subcommand, and *not* a flag or class parameter
+                return self.initialize_subcommand(subc, subargv)
+
+        # Arguments after a '--' argument are for the script IPython may be
+        # about to run, not IPython iteslf. For arguments parsed here (help and
+        # version), we want to only search the arguments up to the first
+        # occurrence of '--', which we're calling interpreted_argv.
+        try:
+            interpreted_argv = argv[:argv.index('--')]
+        except ValueError:
+            interpreted_argv = argv
+
+        if any(x in interpreted_argv for x in ('-h', '--help-all', '--help')):
+            self.print_help('--help-all' in interpreted_argv)
+            self.exit(0)
+
+        if '--version' in interpreted_argv or '-V' in interpreted_argv:
+            self.print_version()
+            self.exit(0)
+
+        # flatten flags&aliases, so cl-args get appropriate priority:
+        flags,aliases = self.flatten_flags()
+        loader = KVArgParseConfigLoader(argv=argv, aliases=aliases,
+                                        flags=flags, log=self.log)
+        self.cli_config = deepcopy(loader.load_config())
+        self.update_config(self.cli_config)
+        # store unparsed args in extra_args
+        self.extra_args = loader.extra_args
+
+    @classmethod
+    def _load_config_files(cls, basefilename, path=None, log=None, raise_config_file_errors=False):
+        """Load config files (py,json) by filename and path.
+
+        yield each config object in turn.
+        """
+
+        if not isinstance(path, list):
+            path = [path]
+        for path in path[::-1]:
+            # path list is in descending priority order, so load files backwards:
+            pyloader = cls.python_config_loader_class(basefilename+'.py', path=path, log=log)
+            if log:
+                log.debug("Looking for %s in %s", basefilename, path or os.getcwd())
+            jsonloader = cls.json_config_loader_class(basefilename+'.json', path=path, log=log)
+            loaded = []
+            filenames = []
+            for loader in [pyloader, jsonloader]:
+                config = None
+                try:
+                    config = loader.load_config()
+                except ConfigFileNotFound:
+                    pass
+                except Exception:
+                    # try to get the full filename, but it will be empty in the
+                    # unlikely event that the error raised before filefind finished
+                    filename = loader.full_filename or basefilename
+                    # problem while running the file
+                    if raise_config_file_errors:
+                        raise
+                    if log:
+                        log.error("Exception while loading config file %s",
+                                filename, exc_info=True)
+                else:
+                    if log:
+                        log.debug("Loaded config file: %s", loader.full_filename)
+                if config:
+                    for filename, earlier_config in zip(filenames, loaded):
+                        collisions = earlier_config.collisions(config)
+                        if collisions and log:
+                            log.warning("Collisions detected in {0} and {1} config files."
+                                " {1} has higher priority: {2}".format(
+                                filename, loader.full_filename, json.dumps(collisions, indent=2),
+                            ))
+                    yield (config, loader.full_filename)
+                    loaded.append(config)
+                    filenames.append(loader.full_filename)
+
+    @property
+    def loaded_config_files(self):
+        """Currently loaded configuration files"""
+        return self._loaded_config_files[:]
+
+    @catch_config_error
+    def load_config_file(self, filename, path=None):
+        """Load config files by filename and path."""
+        filename, ext = os.path.splitext(filename)
+        new_config = Config()
+        for (config, filename) in self._load_config_files(filename, path=path, log=self.log,
+            raise_config_file_errors=self.raise_config_file_errors,
+        ):
+            new_config.merge(config)
+            if filename not in self._loaded_config_files:  # only add to list of loaded files if not previously loaded
+                self._loaded_config_files.append(filename)
+        # add self.cli_config to preserve CLI config priority
+        new_config.merge(self.cli_config)
+        self.update_config(new_config)
+
+
+    def _classes_in_config_sample(self):
+        """
+        Yields only classes with own traits, and their subclasses.
+
+        Thus, produced sample config-file will contain all classes
+        on which a trait-value may be overridden:
+
+        - either on the class owning the trait,
+        - or on its subclasses, even if those subclasses do not define
+          any traits themselves.
+        """
+        cls_to_config = OrderedDict( (cls, bool(cls.class_own_traits(config=True)))
+                              for cls
+                              in self._classes_inc_parents())
+
+        def is_any_parent_included(cls):
+            return any(b in cls_to_config and cls_to_config[b] for b in cls.__bases__)
+
+        ## Mark "empty" classes for inclusion if their parents own-traits,
+        #  and loop until no more classes gets marked.
+        #
+        while True:
+            to_incl_orig = cls_to_config.copy()
+            cls_to_config = OrderedDict( (cls, inc_yes or is_any_parent_included(cls))
+                                  for cls, inc_yes
+                                  in cls_to_config.items())
+            if cls_to_config == to_incl_orig:
+                break
+        for cl, inc_yes in cls_to_config.items():
+            if inc_yes:
+                yield cl
+
+    def generate_config_file(self):
+        """generate default config file from Configurables"""
+        lines = ["# Configuration file for %s." % self.name]
+        lines.append('')
+        for cls in self._classes_in_config_sample():
+            lines.append(cls.class_config_section())
+        return '\n'.join(lines)
+
+    def exit(self, exit_status=0):
+        self.log.debug("Exiting application: %s" % self.name)
+        sys.exit(exit_status)
+
+    @classmethod
+    def launch_instance(cls, argv=None, **kwargs):
+        """Launch a global instance of this Application
+
+        If a global instance already exists, this reinitializes and starts it
+        """
+        app = cls.instance(**kwargs)
+        app.initialize(argv)
+        app.start()
+
+#-----------------------------------------------------------------------------
+# utility functions, for convenience
+#-----------------------------------------------------------------------------
+
+def boolean_flag(name, configurable, set_help='', unset_help=''):
+    """Helper for building basic --trait, --no-trait flags.
+
+    Parameters
+    ----------
+
+    name : str
+        The name of the flag.
+    configurable : str
+        The 'Class.trait' string of the trait to be set/unset with the flag
+    set_help : unicode
+        help string for --name flag
+    unset_help : unicode
+        help string for --no-name flag
+
+    Returns
+    -------
+
+    cfg : dict
+        A dict with two keys: 'name', and 'no-name', for setting and unsetting
+        the trait, respectively.
+    """
+    # default helpstrings
+    set_help = set_help or "set %s=True"%configurable
+    unset_help = unset_help or "set %s=False"%configurable
+
+    cls,trait = configurable.split('.')
+
+    setter = {cls : {trait : True}}
+    unsetter = {cls : {trait : False}}
+    return {name : (setter, set_help), 'no-'+name : (unsetter, unset_help)}
+
+
+def get_config():
+    """Get the config object for the global Application instance, if there is one
+
+    otherwise return an empty config object
+    """
+    if Application.initialized():
+        return Application.instance().config
+    else:
+        return Config()

venv/Lib/site-packages/traitlets/config/configurable.py

@@ -0,0 +1,432 @@
+# encoding: utf-8
+"""A base class for objects that are configurable."""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+from __future__ import print_function, absolute_import
+
+from copy import deepcopy
+import warnings
+
+from .loader import Config, LazyConfigValue, _is_section_key
+from traitlets.traitlets import HasTraits, Instance, observe, observe_compat, default
+from ipython_genutils.text import indent, dedent, wrap_paragraphs
+
+
+#-----------------------------------------------------------------------------
+# Helper classes for Configurables
+#-----------------------------------------------------------------------------
+
+
+class ConfigurableError(Exception):
+    pass
+
+
+class MultipleInstanceError(ConfigurableError):
+    pass
+
+#-----------------------------------------------------------------------------
+# Configurable implementation
+#-----------------------------------------------------------------------------
+
+class Configurable(HasTraits):
+
+    config = Instance(Config, (), {})
+    parent = Instance('traitlets.config.configurable.Configurable', allow_none=True)
+
+    def __init__(self, **kwargs):
+        """Create a configurable given a config config.
+
+        Parameters
+        ----------
+        config : Config
+            If this is empty, default values are used. If config is a
+            :class:`Config` instance, it will be used to configure the
+            instance.
+        parent : Configurable instance, optional
+            The parent Configurable instance of this object.
+
+        Notes
+        -----
+        Subclasses of Configurable must call the :meth:`__init__` method of
+        :class:`Configurable` *before* doing anything else and using
+        :func:`super`::
+
+            class MyConfigurable(Configurable):
+                def __init__(self, config=None):
+                    super(MyConfigurable, self).__init__(config=config)
+                    # Then any other code you need to finish initialization.
+
+        This ensures that instances will be configured properly.
+        """
+        parent = kwargs.pop('parent', None)
+        if parent is not None:
+            # config is implied from parent
+            if kwargs.get('config', None) is None:
+                kwargs['config'] = parent.config
+            self.parent = parent
+
+        config = kwargs.pop('config', None)
+
+        # load kwarg traits, other than config
+        super(Configurable, self).__init__(**kwargs)
+
+        # load config
+        if config is not None:
+            # We used to deepcopy, but for now we are trying to just save
+            # by reference.  This *could* have side effects as all components
+            # will share config. In fact, I did find such a side effect in
+            # _config_changed below. If a config attribute value was a mutable type
+            # all instances of a component were getting the same copy, effectively
+            # making that a class attribute.
+            # self.config = deepcopy(config)
+            self.config = config
+        else:
+            # allow _config_default to return something
+            self._load_config(self.config)
+
+        # Ensure explicit kwargs are applied after loading config.
+        # This is usually redundant, but ensures config doesn't override
+        # explicitly assigned values.
+        for key, value in kwargs.items():
+            setattr(self, key, value)
+
+    #-------------------------------------------------------------------------
+    # Static trait notifiations
+    #-------------------------------------------------------------------------
+
+    @classmethod
+    def section_names(cls):
+        """return section names as a list"""
+        return  [c.__name__ for c in reversed(cls.__mro__) if
+            issubclass(c, Configurable) and issubclass(cls, c)
+        ]
+
+    def _find_my_config(self, cfg):
+        """extract my config from a global Config object
+
+        will construct a Config object of only the config values that apply to me
+        based on my mro(), as well as those of my parent(s) if they exist.
+
+        If I am Bar and my parent is Foo, and their parent is Tim,
+        this will return merge following config sections, in this order::
+
+            [Bar, Foo.bar, Tim.Foo.Bar]
+
+        With the last item being the highest priority.
+        """
+        cfgs = [cfg]
+        if self.parent:
+            cfgs.append(self.parent._find_my_config(cfg))
+        my_config = Config()
+        for c in cfgs:
+            for sname in self.section_names():
+                # Don't do a blind getattr as that would cause the config to
+                # dynamically create the section with name Class.__name__.
+                if c._has_section(sname):
+                    my_config.merge(c[sname])
+        return my_config
+
+    def _load_config(self, cfg, section_names=None, traits=None):
+        """load traits from a Config object"""
+
+        if traits is None:
+            traits = self.traits(config=True)
+        if section_names is None:
+            section_names = self.section_names()
+
+        my_config = self._find_my_config(cfg)
+
+        # hold trait notifications until after all config has been loaded
+        with self.hold_trait_notifications():
+            for name, config_value in my_config.items():
+                if name in traits:
+                    if isinstance(config_value, LazyConfigValue):
+                        # ConfigValue is a wrapper for using append / update on containers
+                        # without having to copy the initial value
+                        initial = getattr(self, name)
+                        config_value = config_value.get_value(initial)
+                    # We have to do a deepcopy here if we don't deepcopy the entire
+                    # config object. If we don't, a mutable config_value will be
+                    # shared by all instances, effectively making it a class attribute.
+                    setattr(self, name, deepcopy(config_value))
+                elif not _is_section_key(name) and not isinstance(config_value, Config):
+                    from difflib import get_close_matches
+                    if isinstance(self, LoggingConfigurable):
+                        warn = self.log.warning
+                    else:
+                        warn = lambda msg: warnings.warn(msg, stacklevel=9)
+                    matches = get_close_matches(name, traits)
+                    msg = u"Config option `{option}` not recognized by `{klass}`.".format(
+                        option=name, klass=self.__class__.__name__)
+
+                    if len(matches) == 1:
+                        msg += u"  Did you mean `{matches}`?".format(matches=matches[0])
+                    elif len(matches) >= 1:
+                        msg +="  Did you mean one of: `{matches}`?".format(matches=', '.join(sorted(matches)))
+                    warn(msg)
+
+    @observe('config')
+    @observe_compat
+    def _config_changed(self, change):
+        """Update all the class traits having ``config=True`` in metadata.
+
+        For any class trait with a ``config`` metadata attribute that is
+        ``True``, we update the trait with the value of the corresponding
+        config entry.
+        """
+        # Get all traits with a config metadata entry that is True
+        traits = self.traits(config=True)
+
+        # We auto-load config section for this class as well as any parent
+        # classes that are Configurable subclasses.  This starts with Configurable
+        # and works down the mro loading the config for each section.
+        section_names = self.section_names()
+        self._load_config(change.new, traits=traits, section_names=section_names)
+
+    def update_config(self, config):
+        """Update config and load the new values"""
+        # traitlets prior to 4.2 created a copy of self.config in order to trigger change events.
+        # Some projects (IPython < 5) relied upon one side effect of this,
+        # that self.config prior to update_config was not modified in-place.
+        # For backward-compatibility, we must ensure that self.config
+        # is a new object and not modified in-place,
+        # but config consumers should not rely on this behavior.
+        self.config = deepcopy(self.config)
+        # load config
+        self._load_config(config)
+        # merge it into self.config
+        self.config.merge(config)
+        # TODO: trigger change event if/when dict-update change events take place
+        # DO NOT trigger full trait-change
+
+    @classmethod
+    def class_get_help(cls, inst=None):
+        """Get the help string for this class in ReST format.
+
+        If `inst` is given, it's current trait values will be used in place of
+        class defaults.
+        """
+        assert inst is None or isinstance(inst, cls)
+        final_help = []
+        final_help.append(u'%s options' % cls.__name__)
+        final_help.append(len(final_help[0])*u'-')
+        for k, v in sorted(cls.class_traits(config=True).items()):
+            help = cls.class_get_trait_help(v, inst)
+            final_help.append(help)
+        return '\n'.join(final_help)
+
+    @classmethod
+    def class_get_trait_help(cls, trait, inst=None):
+        """Get the help string for a single trait.
+
+        If `inst` is given, it's current trait values will be used in place of
+        the class default.
+        """
+        assert inst is None or isinstance(inst, cls)
+        lines = []
+        header = "--%s.%s=<%s>" % (cls.__name__, trait.name, trait.__class__.__name__)
+        lines.append(header)
+        if inst is not None:
+            lines.append(indent('Current: %r' % getattr(inst, trait.name), 4))
+        else:
+            try:
+                dvr = trait.default_value_repr()
+            except Exception:
+                dvr = None # ignore defaults we can't construct
+            if dvr is not None:
+                if len(dvr) > 64:
+                    dvr = dvr[:61]+'...'
+                lines.append(indent('Default: %s' % dvr, 4))
+        if 'Enum' in trait.__class__.__name__:
+            # include Enum choices
+            lines.append(indent('Choices: %r' % (trait.values,)))
+
+        help = trait.help
+        if help != '':
+            help = '\n'.join(wrap_paragraphs(help, 76))
+            lines.append(indent(help, 4))
+        return '\n'.join(lines)
+
+    @classmethod
+    def class_print_help(cls, inst=None):
+        """Get the help string for a single trait and print it."""
+        print(cls.class_get_help(inst))
+
+    @classmethod
+    def class_config_section(cls):
+        """Get the config class config section"""
+        def c(s):
+            """return a commented, wrapped block."""
+            s = '\n\n'.join(wrap_paragraphs(s, 78))
+
+            return '## ' + s.replace('\n', '\n#  ')
+
+        # section header
+        breaker = '#' + '-'*78
+        parent_classes = ','.join(p.__name__ for p in cls.__bases__)
+        s = "# %s(%s) configuration" % (cls.__name__, parent_classes)
+        lines = [breaker, s, breaker, '']
+        # get the description trait
+        desc = cls.class_traits().get('description')
+        if desc:
+            desc = desc.default_value
+        if not desc:
+            # no description from trait, use __doc__
+            desc = getattr(cls, '__doc__', '')
+        if desc:
+            lines.append(c(desc))
+            lines.append('')
+
+        for name, trait in sorted(cls.class_own_traits(config=True).items()):
+            lines.append(c(trait.help))
+            lines.append('#c.%s.%s = %s' % (cls.__name__, name, trait.default_value_repr()))
+            lines.append('')
+        return '\n'.join(lines)
+
+    @classmethod
+    def class_config_rst_doc(cls):
+        """Generate rST documentation for this class' config options.
+
+        Excludes traits defined on parent classes.
+        """
+        lines = []
+        classname = cls.__name__
+        for k, trait in sorted(cls.class_own_traits(config=True).items()):
+            ttype = trait.__class__.__name__
+
+            termline = classname + '.' + trait.name
+
+            # Choices or type
+            if 'Enum' in ttype:
+                # include Enum choices
+                termline += ' : ' + '|'.join(repr(x) for x in trait.values)
+            else:
+                termline += ' : ' + ttype
+            lines.append(termline)
+
+            # Default value
+            try:
+                dvr = trait.default_value_repr()
+            except Exception:
+                dvr = None # ignore defaults we can't construct
+            if dvr is not None:
+                if len(dvr) > 64:
+                    dvr = dvr[:61]+'...'
+                # Double up backslashes, so they get to the rendered docs
+                dvr = dvr.replace('\\n', '\\\\n')
+                lines.append('    Default: ``%s``' % dvr)
+                lines.append('')
+
+            help = trait.help or 'No description'
+            lines.append(indent(dedent(help), 4))
+
+            # Blank line
+            lines.append('')
+
+        return '\n'.join(lines)
+
+
+
+class LoggingConfigurable(Configurable):
+    """A parent class for Configurables that log.
+
+    Subclasses have a log trait, and the default behavior
+    is to get the logger from the currently running Application.
+    """
+
+    log = Instance('logging.Logger')
+    @default('log')
+    def _log_default(self):
+        from traitlets import log
+        return log.get_logger()
+
+
+class SingletonConfigurable(LoggingConfigurable):
+    """A configurable that only allows one instance.
+
+    This class is for classes that should only have one instance of itself
+    or *any* subclass. To create and retrieve such a class use the
+    :meth:`SingletonConfigurable.instance` method.
+    """
+
+    _instance = None
+
+    @classmethod
+    def _walk_mro(cls):
+        """Walk the cls.mro() for parent classes that are also singletons
+
+        For use in instance()
+        """
+
+        for subclass in cls.mro():
+            if issubclass(cls, subclass) and \
+                    issubclass(subclass, SingletonConfigurable) and \
+                    subclass != SingletonConfigurable:
+                yield subclass
+
+    @classmethod
+    def clear_instance(cls):
+        """unset _instance for this class and singleton parents.
+        """
+        if not cls.initialized():
+            return
+        for subclass in cls._walk_mro():
+            if isinstance(subclass._instance, cls):
+                # only clear instances that are instances
+                # of the calling class
+                subclass._instance = None
+
+    @classmethod
+    def instance(cls, *args, **kwargs):
+        """Returns a global instance of this class.
+
+        This method create a new instance if none have previously been created
+        and returns a previously created instance is one already exists.
+
+        The arguments and keyword arguments passed to this method are passed
+        on to the :meth:`__init__` method of the class upon instantiation.
+
+        Examples
+        --------
+
+        Create a singleton class using instance, and retrieve it::
+
+            >>> from traitlets.config.configurable import SingletonConfigurable
+            >>> class Foo(SingletonConfigurable): pass
+            >>> foo = Foo.instance()
+            >>> foo == Foo.instance()
+            True
+
+        Create a subclass that is retrived using the base class instance::
+
+            >>> class Bar(SingletonConfigurable): pass
+            >>> class Bam(Bar): pass
+            >>> bam = Bam.instance()
+            >>> bam == Bar.instance()
+            True
+        """
+        # Create and save the instance
+        if cls._instance is None:
+            inst = cls(*args, **kwargs)
+            # Now make sure that the instance will also be returned by
+            # parent classes' _instance attribute.
+            for subclass in cls._walk_mro():
+                subclass._instance = inst
+
+        if isinstance(cls._instance, cls):
+            return cls._instance
+        else:
+            raise MultipleInstanceError(
+                'Multiple incompatible subclass instances of '
+                '%s are being created.' % cls.__name__
+            )
+
+    @classmethod
+    def initialized(cls):
+        """Has an instance been created?"""
+        return hasattr(cls, "_instance") and cls._instance is not None
+
+
+

venv/Lib/site-packages/traitlets/config/loader.py

@@ -0,0 +1,857 @@
+# encoding: utf-8
+"""A simple configuration system."""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+import argparse
+import copy
+import logging
+import os
+import re
+import sys
+import json
+from ast import literal_eval
+
+from ipython_genutils.path import filefind
+from ipython_genutils import py3compat
+from ipython_genutils.encoding import DEFAULT_ENCODING
+from six import text_type
+from traitlets.traitlets import HasTraits, List, Any
+
+#-----------------------------------------------------------------------------
+# Exceptions
+#-----------------------------------------------------------------------------
+
+
+class ConfigError(Exception):
+    pass
+
+class ConfigLoaderError(ConfigError):
+    pass
+
+class ConfigFileNotFound(ConfigError):
+    pass
+
+class ArgumentError(ConfigLoaderError):
+    pass
+
+#-----------------------------------------------------------------------------
+# Argparse fix
+#-----------------------------------------------------------------------------
+
+# Unfortunately argparse by default prints help messages to stderr instead of
+# stdout.  This makes it annoying to capture long help screens at the command
+# line, since one must know how to pipe stderr, which many users don't know how
+# to do.  So we override the print_help method with one that defaults to
+# stdout and use our class instead.
+
+class ArgumentParser(argparse.ArgumentParser):
+    """Simple argparse subclass that prints help to stdout by default."""
+
+    def print_help(self, file=None):
+        if file is None:
+            file = sys.stdout
+        return super(ArgumentParser, self).print_help(file)
+
+    print_help.__doc__ = argparse.ArgumentParser.print_help.__doc__
+
+#-----------------------------------------------------------------------------
+# Config class for holding config information
+#-----------------------------------------------------------------------------
+
+class LazyConfigValue(HasTraits):
+    """Proxy object for exposing methods on configurable containers
+    
+    Exposes:
+    
+    - append, extend, insert on lists
+    - update on dicts
+    - update, add on sets
+    """
+    
+    _value = None
+    
+    # list methods
+    _extend = List()
+    _prepend = List()
+    
+    def append(self, obj):
+        self._extend.append(obj)
+    
+    def extend(self, other):
+        self._extend.extend(other)
+    
+    def prepend(self, other):
+        """like list.extend, but for the front"""
+        self._prepend[:0] = other
+    
+    _inserts = List()
+    def insert(self, index, other):
+        if not isinstance(index, int):
+            raise TypeError("An integer is required")
+        self._inserts.append((index, other))
+    
+    # dict methods
+    # update is used for both dict and set
+    _update = Any()
+    def update(self, other):
+        if self._update is None:
+            if isinstance(other, dict):
+                self._update = {}
+            else:
+                self._update = set()
+        self._update.update(other)
+    
+    # set methods
+    def add(self, obj):
+        self.update({obj})
+    
+    def get_value(self, initial):
+        """construct the value from the initial one
+        
+        after applying any insert / extend / update changes
+        """
+        if self._value is not None:
+            return self._value
+        value = copy.deepcopy(initial)
+        if isinstance(value, list):
+            for idx, obj in self._inserts:
+                value.insert(idx, obj)
+            value[:0] = self._prepend
+            value.extend(self._extend)
+        
+        elif isinstance(value, dict):
+            if self._update:
+                value.update(self._update)
+        elif isinstance(value, set):
+            if self._update:
+                value.update(self._update)
+        self._value = value
+        return value
+    
+    def to_dict(self):
+        """return JSONable dict form of my data
+        
+        Currently update as dict or set, extend, prepend as lists, and inserts as list of tuples.
+        """
+        d = {}
+        if self._update:
+            d['update'] = self._update
+        if self._extend:
+            d['extend'] = self._extend
+        if self._prepend:
+            d['prepend'] = self._prepend
+        elif self._inserts:
+            d['inserts'] = self._inserts
+        return d
+
+
+def _is_section_key(key):
+    """Is a Config key a section name (does it start with a capital)?"""
+    if key and key[0].upper()==key[0] and not key.startswith('_'):
+        return True
+    else:
+        return False
+
+
+class Config(dict):
+    """An attribute based dict that can do smart merges."""
+
+    def __init__(self, *args, **kwds):
+        dict.__init__(self, *args, **kwds)
+        self._ensure_subconfig()
+    
+    def _ensure_subconfig(self):
+        """ensure that sub-dicts that should be Config objects are
+        
+        casts dicts that are under section keys to Config objects,
+        which is necessary for constructing Config objects from dict literals.
+        """
+        for key in self:
+            obj = self[key]
+            if _is_section_key(key) \
+                    and isinstance(obj, dict) \
+                    and not isinstance(obj, Config):
+                setattr(self, key, Config(obj))
+    
+    def _merge(self, other):
+        """deprecated alias, use Config.merge()"""
+        self.merge(other)
+    
+    def merge(self, other):
+        """merge another config object into this one"""
+        to_update = {}
+        for k, v in other.items():
+            if k not in self:
+                to_update[k] = v
+            else: # I have this key
+                if isinstance(v, Config) and isinstance(self[k], Config):
+                    # Recursively merge common sub Configs
+                    self[k].merge(v)
+                else:
+                    # Plain updates for non-Configs
+                    to_update[k] = v
+
+        self.update(to_update)
+    
+    def collisions(self, other):
+        """Check for collisions between two config objects.
+        
+        Returns a dict of the form {"Class": {"trait": "collision message"}}`,
+        indicating which values have been ignored.
+        
+        An empty dict indicates no collisions.
+        """
+        collisions = {}
+        for section in self:
+            if section not in other:
+                continue
+            mine = self[section]
+            theirs = other[section]
+            for key in mine:
+                if key in theirs and mine[key] != theirs[key]:
+                    collisions.setdefault(section, {})
+                    collisions[section][key] = "%r ignored, using %r" % (mine[key], theirs[key])
+        return collisions
+    
+    def __contains__(self, key):
+        # allow nested contains of the form `"Section.key" in config`
+        if '.' in key:
+            first, remainder = key.split('.', 1)
+            if first not in self:
+                return False
+            return remainder in self[first]
+        
+        return super(Config, self).__contains__(key)
+    
+    # .has_key is deprecated for dictionaries.
+    has_key = __contains__
+    
+    def _has_section(self, key):
+        return _is_section_key(key) and key in self
+    
+    def copy(self):
+        return type(self)(dict.copy(self))
+
+    def __copy__(self):
+        return self.copy()
+
+    def __deepcopy__(self, memo):
+        new_config = type(self)()
+        for key, value in self.items():
+            if isinstance(value, (Config, LazyConfigValue)):
+                # deep copy config objects
+                value = copy.deepcopy(value, memo)
+            elif type(value) in {dict, list, set, tuple}:
+                # shallow copy plain container traits
+                value = copy.copy(value)
+            new_config[key] = value
+        return new_config
+    
+    def __getitem__(self, key):
+        try:
+            return dict.__getitem__(self, key)
+        except KeyError:
+            if _is_section_key(key):
+                c = Config()
+                dict.__setitem__(self, key, c)
+                return c
+            elif not key.startswith('_'):
+                # undefined, create lazy value, used for container methods
+                v = LazyConfigValue()
+                dict.__setitem__(self, key, v)
+                return v
+            else:
+                raise KeyError
+
+    def __setitem__(self, key, value):
+        if _is_section_key(key):
+            if not isinstance(value, Config):
+                raise ValueError('values whose keys begin with an uppercase '
+                                 'char must be Config instances: %r, %r' % (key, value))
+        dict.__setitem__(self, key, value)
+
+    def __getattr__(self, key):
+        if key.startswith('__'):
+            return dict.__getattr__(self, key)
+        try:
+            return self.__getitem__(key)
+        except KeyError as e:
+            raise AttributeError(e)
+
+    def __setattr__(self, key, value):
+        if key.startswith('__'):
+            return dict.__setattr__(self, key, value)
+        try:
+            self.__setitem__(key, value)
+        except KeyError as e:
+            raise AttributeError(e)
+
+    def __delattr__(self, key):
+        if key.startswith('__'):
+            return dict.__delattr__(self, key)
+        try:
+            dict.__delitem__(self, key)
+        except KeyError as e:
+            raise AttributeError(e)
+
+
+#-----------------------------------------------------------------------------
+# Config loading classes
+#-----------------------------------------------------------------------------
+
+
+class ConfigLoader(object):
+    """A object for loading configurations from just about anywhere.
+
+    The resulting configuration is packaged as a :class:`Config`.
+
+    Notes
+    -----
+    A :class:`ConfigLoader` does one thing: load a config from a source
+    (file, command line arguments) and returns the data as a :class:`Config` object.
+    There are lots of things that :class:`ConfigLoader` does not do.  It does
+    not implement complex logic for finding config files.  It does not handle
+    default values or merge multiple configs.  These things need to be
+    handled elsewhere.
+    """
+
+    def _log_default(self):
+        from traitlets.log import get_logger
+        return get_logger()
+
+    def __init__(self, log=None):
+        """A base class for config loaders.
+
+        log : instance of :class:`logging.Logger` to use.
+              By default loger of :meth:`traitlets.config.application.Application.instance()`
+              will be used
+
+        Examples
+        --------
+
+        >>> cl = ConfigLoader()
+        >>> config = cl.load_config()
+        >>> config
+        {}
+        """
+        self.clear()
+        if log is None:
+            self.log = self._log_default()
+            self.log.debug('Using default logger')
+        else:
+            self.log = log
+
+    def clear(self):
+        self.config = Config()
+
+    def load_config(self):
+        """Load a config from somewhere, return a :class:`Config` instance.
+
+        Usually, this will cause self.config to be set and then returned.
+        However, in most cases, :meth:`ConfigLoader.clear` should be called
+        to erase any previous state.
+        """
+        self.clear()
+        return self.config
+
+
+class FileConfigLoader(ConfigLoader):
+    """A base class for file based configurations.
+
+    As we add more file based config loaders, the common logic should go
+    here.
+    """
+
+    def __init__(self, filename, path=None, **kw):
+        """Build a config loader for a filename and path.
+
+        Parameters
+        ----------
+        filename : str
+            The file name of the config file.
+        path : str, list, tuple
+            The path to search for the config file on, or a sequence of
+            paths to try in order.
+        """
+        super(FileConfigLoader, self).__init__(**kw)
+        self.filename = filename
+        self.path = path
+        self.full_filename = ''
+
+    def _find_file(self):
+        """Try to find the file by searching the paths."""
+        self.full_filename = filefind(self.filename, self.path)
+
+class JSONFileConfigLoader(FileConfigLoader):
+    """A JSON file loader for config
+
+    Can also act as a context manager that rewrite the configuration file to disk on exit.
+
+    Example::
+
+        with JSONFileConfigLoader('myapp.json','/home/jupyter/configurations/') as c:
+            c.MyNewConfigurable.new_value = 'Updated'
+
+    """
+
+    def load_config(self):
+        """Load the config from a file and return it as a Config object."""
+        self.clear()
+        try:
+            self._find_file()
+        except IOError as e:
+            raise ConfigFileNotFound(str(e))
+        dct = self._read_file_as_dict()
+        self.config = self._convert_to_config(dct)
+        return self.config
+
+    def _read_file_as_dict(self):
+        with open(self.full_filename) as f:
+            return json.load(f)
+
+    def _convert_to_config(self, dictionary):
+        if 'version' in dictionary:
+            version = dictionary.pop('version')
+        else:
+            version = 1
+
+        if version == 1:
+            return Config(dictionary)
+        else:
+            raise ValueError('Unknown version of JSON config file: {version}'.format(version=version))
+
+    def __enter__(self):
+        self.load_config()
+        return self.config
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        """
+        Exit the context manager but do not handle any errors.
+
+        In case of any error, we do not want to write the potentially broken
+        configuration to disk.
+        """
+        self.config.version = 1
+        json_config = json.dumps(self.config, indent=2)
+        with open(self.full_filename, 'w') as f:
+            f.write(json_config)
+
+
+
+class PyFileConfigLoader(FileConfigLoader):
+    """A config loader for pure python files.
+
+    This is responsible for locating a Python config file by filename and
+    path, then executing it to construct a Config object.
+    """
+
+    def load_config(self):
+        """Load the config from a file and return it as a Config object."""
+        self.clear()
+        try:
+            self._find_file()
+        except IOError as e:
+            raise ConfigFileNotFound(str(e))
+        self._read_file_as_dict()
+        return self.config
+    
+    def load_subconfig(self, fname, path=None):
+        """Injected into config file namespace as load_subconfig"""
+        if path is None:
+            path = self.path
+        
+        loader = self.__class__(fname, path)
+        try:
+            sub_config = loader.load_config()
+        except ConfigFileNotFound:
+            # Pass silently if the sub config is not there,
+            # treat it as an empty config file.
+            pass
+        else:
+            self.config.merge(sub_config)
+    
+    def _read_file_as_dict(self):
+        """Load the config file into self.config, with recursive loading."""
+        def get_config():
+            """Unnecessary now, but a deprecation warning is more trouble than it's worth."""
+            return self.config
+        
+        namespace = dict(
+            c=self.config,
+            load_subconfig=self.load_subconfig,
+            get_config=get_config,
+            __file__=self.full_filename,
+        )
+        fs_encoding = sys.getfilesystemencoding() or 'ascii'
+        conf_filename = self.full_filename.encode(fs_encoding)
+        py3compat.execfile(conf_filename, namespace)
+
+
+class CommandLineConfigLoader(ConfigLoader):
+    """A config loader for command line arguments.
+
+    As we add more command line based loaders, the common logic should go
+    here.
+    """
+
+    def _exec_config_str(self, lhs, rhs):
+        """execute self.config.<lhs> = <rhs>
+        
+        * expands ~ with expanduser
+        * tries to assign with literal_eval, otherwise assigns with just the string,
+          allowing `--C.a=foobar` and `--C.a="foobar"` to be equivalent.  *Not*
+          equivalent are `--C.a=4` and `--C.a='4'`.
+        """
+        rhs = os.path.expanduser(rhs)
+        try:
+            # Try to see if regular Python syntax will work. This
+            # won't handle strings as the quote marks are removed
+            # by the system shell.
+            value = literal_eval(rhs)
+        except (NameError, SyntaxError, ValueError):
+            # This case happens if the rhs is a string.
+            value = rhs
+
+        exec(u'self.config.%s = value' % lhs)
+
+    def _load_flag(self, cfg):
+        """update self.config from a flag, which can be a dict or Config"""
+        if isinstance(cfg, (dict, Config)):
+            # don't clobber whole config sections, update
+            # each section from config:
+            for sec,c in cfg.items():
+                self.config[sec].update(c)
+        else:
+            raise TypeError("Invalid flag: %r" % cfg)
+
+# raw --identifier=value pattern
+# but *also* accept '-' as wordsep, for aliases
+# accepts:  --foo=a
+#           --Class.trait=value
+#           --alias-name=value
+# rejects:  -foo=value
+#           --foo
+#           --Class.trait
+kv_pattern = re.compile(r'\-\-[A-Za-z][\w\-]*(\.[\w\-]+)*\=.*')
+
+# just flags, no assignments, with two *or one* leading '-'
+# accepts:  --foo
+#           -foo-bar-again
+# rejects:  --anything=anything
+#           --two.word
+
+flag_pattern = re.compile(r'\-\-?\w+[\-\w]*$')
+
+class KeyValueConfigLoader(CommandLineConfigLoader):
+    """A config loader that loads key value pairs from the command line.
+
+    This allows command line options to be gives in the following form::
+
+        ipython --profile="foo" --InteractiveShell.autocall=False
+    """
+
+    def __init__(self, argv=None, aliases=None, flags=None, **kw):
+        """Create a key value pair config loader.
+
+        Parameters
+        ----------
+        argv : list
+            A list that has the form of sys.argv[1:] which has unicode
+            elements of the form u"key=value". If this is None (default),
+            then sys.argv[1:] will be used.
+        aliases : dict
+            A dict of aliases for configurable traits.
+            Keys are the short aliases, Values are the resolved trait.
+            Of the form: `{'alias' : 'Configurable.trait'}`
+        flags : dict
+            A dict of flags, keyed by str name. Vaues can be Config objects,
+            dicts, or "key=value" strings.  If Config or dict, when the flag
+            is triggered, The flag is loaded as `self.config.update(m)`.
+
+        Returns
+        -------
+        config : Config
+            The resulting Config object.
+
+        Examples
+        --------
+
+            >>> from traitlets.config.loader import KeyValueConfigLoader
+            >>> cl = KeyValueConfigLoader()
+            >>> d = cl.load_config(["--A.name='brian'","--B.number=0"])
+            >>> sorted(d.items())
+            [('A', {'name': 'brian'}), ('B', {'number': 0})]
+        """
+        super(KeyValueConfigLoader, self).__init__(**kw)
+        if argv is None:
+            argv = sys.argv[1:]
+        self.argv = argv
+        self.aliases = aliases or {}
+        self.flags = flags or {}
+
+
+    def clear(self):
+        super(KeyValueConfigLoader, self).clear()
+        self.extra_args = []
+
+
+    def _decode_argv(self, argv, enc=None):
+        """decode argv if bytes, using stdin.encoding, falling back on default enc"""
+        uargv = []
+        if enc is None:
+            enc = DEFAULT_ENCODING
+        for arg in argv:
+            if not isinstance(arg, text_type):
+                # only decode if not already decoded
+                arg = arg.decode(enc)
+            uargv.append(arg)
+        return uargv
+
+
+    def load_config(self, argv=None, aliases=None, flags=None):
+        """Parse the configuration and generate the Config object.
+
+        After loading, any arguments that are not key-value or
+        flags will be stored in self.extra_args - a list of
+        unparsed command-line arguments.  This is used for
+        arguments such as input files or subcommands.
+
+        Parameters
+        ----------
+        argv : list, optional
+            A list that has the form of sys.argv[1:] which has unicode
+            elements of the form u"key=value". If this is None (default),
+            then self.argv will be used.
+        aliases : dict
+            A dict of aliases for configurable traits.
+            Keys are the short aliases, Values are the resolved trait.
+            Of the form: `{'alias' : 'Configurable.trait'}`
+        flags : dict
+            A dict of flags, keyed by str name. Values can be Config objects
+            or dicts.  When the flag is triggered, The config is loaded as
+            `self.config.update(cfg)`.
+        """
+        self.clear()
+        if argv is None:
+            argv = self.argv
+        if aliases is None:
+            aliases = self.aliases
+        if flags is None:
+            flags = self.flags
+
+        # ensure argv is a list of unicode strings:
+        uargv = self._decode_argv(argv)
+        for idx,raw in enumerate(uargv):
+            # strip leading '-'
+            item = raw.lstrip('-')
+
+            if raw == '--':
+                # don't parse arguments after '--'
+                # this is useful for relaying arguments to scripts, e.g.
+                # ipython -i foo.py --matplotlib=qt -- args after '--' go-to-foo.py
+                self.extra_args.extend(uargv[idx+1:])
+                break
+
+            if kv_pattern.match(raw):
+                lhs,rhs = item.split('=',1)
+                # Substitute longnames for aliases.
+                if lhs in aliases:
+                    lhs = aliases[lhs]
+                if '.' not in lhs:
+                    # probably a mistyped alias, but not technically illegal
+                    self.log.warning("Unrecognized alias: '%s', it will probably have no effect.", raw)
+                try:
+                    self._exec_config_str(lhs, rhs)
+                except Exception:
+                    raise ArgumentError("Invalid argument: '%s'" % raw)
+
+            elif flag_pattern.match(raw):
+                if item in flags:
+                    cfg,help = flags[item]
+                    self._load_flag(cfg)
+                else:
+                    raise ArgumentError("Unrecognized flag: '%s'"%raw)
+            elif raw.startswith('-'):
+                kv = '--'+item
+                if kv_pattern.match(kv):
+                    raise ArgumentError("Invalid argument: '%s', did you mean '%s'?"%(raw, kv))
+                else:
+                    raise ArgumentError("Invalid argument: '%s'"%raw)
+            else:
+                # keep all args that aren't valid in a list,
+                # in case our parent knows what to do with them.
+                self.extra_args.append(item)
+        return self.config
+
+class ArgParseConfigLoader(CommandLineConfigLoader):
+    """A loader that uses the argparse module to load from the command line."""
+
+    def __init__(self, argv=None, aliases=None, flags=None, log=None,  *parser_args, **parser_kw):
+        """Create a config loader for use with argparse.
+
+        Parameters
+        ----------
+
+        argv : optional, list
+          If given, used to read command-line arguments from, otherwise
+          sys.argv[1:] is used.
+
+        parser_args : tuple
+          A tuple of positional arguments that will be passed to the
+          constructor of :class:`argparse.ArgumentParser`.
+
+        parser_kw : dict
+          A tuple of keyword arguments that will be passed to the
+          constructor of :class:`argparse.ArgumentParser`.
+
+        Returns
+        -------
+        config : Config
+            The resulting Config object.
+        """
+        super(CommandLineConfigLoader, self).__init__(log=log)
+        self.clear()
+        if argv is None:
+            argv = sys.argv[1:]
+        self.argv = argv
+        self.aliases = aliases or {}
+        self.flags = flags or {}
+
+        self.parser_args = parser_args
+        self.version = parser_kw.pop("version", None)
+        kwargs = dict(argument_default=argparse.SUPPRESS)
+        kwargs.update(parser_kw)
+        self.parser_kw = kwargs
+
+    def load_config(self, argv=None, aliases=None, flags=None):
+        """Parse command line arguments and return as a Config object.
+
+        Parameters
+        ----------
+
+        args : optional, list
+          If given, a list with the structure of sys.argv[1:] to parse
+          arguments from. If not given, the instance's self.argv attribute
+          (given at construction time) is used."""
+        self.clear()
+        if argv is None:
+            argv = self.argv
+        if aliases is None:
+            aliases = self.aliases
+        if flags is None:
+            flags = self.flags
+        self._create_parser(aliases, flags)
+        self._parse_args(argv)
+        self._convert_to_config()
+        return self.config
+
+    def get_extra_args(self):
+        if hasattr(self, 'extra_args'):
+            return self.extra_args
+        else:
+            return []
+
+    def _create_parser(self, aliases=None, flags=None):
+        self.parser = ArgumentParser(*self.parser_args, **self.parser_kw)
+        self._add_arguments(aliases, flags)
+
+    def _add_arguments(self, aliases=None, flags=None):
+        raise NotImplementedError("subclasses must implement _add_arguments")
+
+    def _parse_args(self, args):
+        """self.parser->self.parsed_data"""
+        # decode sys.argv to support unicode command-line options
+        enc = DEFAULT_ENCODING
+        uargs = [py3compat.cast_unicode(a, enc) for a in args]
+        self.parsed_data, self.extra_args = self.parser.parse_known_args(uargs)
+
+    def _convert_to_config(self):
+        """self.parsed_data->self.config"""
+        for k, v in vars(self.parsed_data).items():
+            exec("self.config.%s = v"%k, locals(), globals())
+
+class KVArgParseConfigLoader(ArgParseConfigLoader):
+    """A config loader that loads aliases and flags with argparse,
+    but will use KVLoader for the rest.  This allows better parsing
+    of common args, such as `ipython -c 'print 5'`, but still gets
+    arbitrary config with `ipython --InteractiveShell.use_readline=False`"""
+
+    def _add_arguments(self, aliases=None, flags=None):
+        self.alias_flags = {}
+        # print aliases, flags
+        if aliases is None:
+            aliases = self.aliases
+        if flags is None:
+            flags = self.flags
+        paa = self.parser.add_argument
+        for key,value in aliases.items():
+            if key in flags:
+                # flags
+                nargs = '?'
+            else:
+                nargs = None
+            if len(key) is 1:
+                paa('-'+key, '--'+key, type=text_type, dest=value, nargs=nargs)
+            else:
+                paa('--'+key, type=text_type, dest=value, nargs=nargs)
+        for key, (value, help) in flags.items():
+            if key in self.aliases:
+                #
+                self.alias_flags[self.aliases[key]] = value
+                continue
+            if len(key) is 1:
+                paa('-'+key, '--'+key, action='append_const', dest='_flags', const=value)
+            else:
+                paa('--'+key, action='append_const', dest='_flags', const=value)
+
+    def _convert_to_config(self):
+        """self.parsed_data->self.config, parse unrecognized extra args via KVLoader."""
+        # remove subconfigs list from namespace before transforming the Namespace
+        if '_flags' in self.parsed_data:
+            subcs = self.parsed_data._flags
+            del self.parsed_data._flags
+        else:
+            subcs = []
+
+        for k, v in vars(self.parsed_data).items():
+            if v is None:
+                # it was a flag that shares the name of an alias
+                subcs.append(self.alias_flags[k])
+            else:
+                # eval the KV assignment
+                self._exec_config_str(k, v)
+
+        for subc in subcs:
+            self._load_flag(subc)
+
+        if self.extra_args:
+            sub_parser = KeyValueConfigLoader(log=self.log)
+            sub_parser.load_config(self.extra_args)
+            self.config.merge(sub_parser.config)
+            self.extra_args = sub_parser.extra_args
+
+
+def load_pyconfig_files(config_files, path):
+    """Load multiple Python config files, merging each of them in turn.
+
+    Parameters
+    ==========
+    config_files : list of str
+        List of config files names to load and merge into the config.
+    path : unicode
+        The full path to the location of the config files.
+    """
+    config = Config()
+    for cf in config_files:
+        loader = PyFileConfigLoader(cf, path=path)
+        try:
+            next_config = loader.load_config()
+        except ConfigFileNotFound:
+            pass
+        except:
+            raise
+        else:
+            config.merge(next_config)
+    return config

venv/Lib/site-packages/traitlets/config/manager.py

@@ -0,0 +1,88 @@
+"""Manager to read and modify config data in JSON files.
+"""
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+import errno
+import io
+import json
+import os
+
+from six import PY3
+from traitlets.config import LoggingConfigurable
+from traitlets.traitlets import Unicode
+
+
+def recursive_update(target, new):
+    """Recursively update one dictionary using another.
+
+    None values will delete their keys.
+    """
+    for k, v in new.items():
+        if isinstance(v, dict):
+            if k not in target:
+                target[k] = {}
+            recursive_update(target[k], v)
+            if not target[k]:
+                # Prune empty subdicts
+                del target[k]
+
+        elif v is None:
+            target.pop(k, None)
+
+        else:
+            target[k] = v
+
+
+class BaseJSONConfigManager(LoggingConfigurable):
+    """General JSON config manager
+    
+    Deals with persisting/storing config in a json file
+    """
+
+    config_dir = Unicode('.')
+
+    def ensure_config_dir_exists(self):
+        try:
+            os.makedirs(self.config_dir, 0o755)
+        except OSError as e:
+            if e.errno != errno.EEXIST:
+                raise
+
+    def file_name(self, section_name):
+        return os.path.join(self.config_dir, section_name+'.json')
+
+    def get(self, section_name):
+        """Retrieve the config data for the specified section.
+
+        Returns the data as a dictionary, or an empty dictionary if the file
+        doesn't exist.
+        """
+        filename = self.file_name(section_name)
+        if os.path.isfile(filename):
+            with io.open(filename, encoding='utf-8') as f:
+                return json.load(f)
+        else:
+            return {}
+
+    def set(self, section_name, data):
+        """Store the given config data.
+        """
+        filename = self.file_name(section_name)
+        self.ensure_config_dir_exists()
+
+        if PY3:
+            f = io.open(filename, 'w', encoding='utf-8')
+        else:
+            f = open(filename, 'wb')
+        with f:
+            json.dump(data, f, indent=2)
+
+    def update(self, section_name, new_data):
+        """Modify the config section by recursively updating it with new_data.
+
+        Returns the modified config data as a dictionary.
+        """
+        data = self.get(section_name)
+        recursive_update(data, new_data)
+        self.set(section_name, data)
+        return data

venv/Lib/site-packages/traitlets/config/tests/test_application.py

@@ -0,0 +1,421 @@
+# coding: utf-8
+"""
+Tests for traitlets.config.application.Application
+"""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+import json
+import logging
+import os
+from io import StringIO
+from unittest import TestCase
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
+pjoin = os.path.join
+
+from pytest import mark
+
+from traitlets.config.configurable import Configurable
+from traitlets.config.loader import Config
+from traitlets.tests.utils import check_help_output, check_help_all_output
+
+from traitlets.config.application import (
+    Application
+)
+
+from ipython_genutils.tempdir import TemporaryDirectory
+from traitlets.traitlets import (
+    Bool, Unicode, Integer, List, Dict
+)
+
+
+class Foo(Configurable):
+
+    i = Integer(0, help="The integer i.").tag(config=True)
+    j = Integer(1, help="The integer j.").tag(config=True)
+    name = Unicode(u'Brian', help="First name.").tag(config=True)
+
+
+class Bar(Configurable):
+
+    b = Integer(0, help="The integer b.").tag(config=True)
+    enabled = Bool(True, help="Enable bar.").tag(config=True)
+
+
+class MyApp(Application):
+
+    name = Unicode(u'myapp')
+    running = Bool(False, help="Is the app running?").tag(config=True)
+    classes = List([Bar, Foo])
+    config_file = Unicode(u'', help="Load this config file").tag(config=True)
+
+    warn_tpyo = Unicode(u"yes the name is wrong on purpose", config=True,
+            help="Should print a warning if `MyApp.warn-typo=...` command is passed")
+
+    aliases = Dict({
+                    'i' : 'Foo.i',
+                    'j' : 'Foo.j',
+                    'name' : 'Foo.name',
+                    'enabled' : 'Bar.enabled',
+                    'log-level' : 'Application.log_level',
+                })
+
+    flags = Dict(dict(enable=({'Bar': {'enabled' : True}}, "Set Bar.enabled to True"),
+                  disable=({'Bar': {'enabled' : False}}, "Set Bar.enabled to False"),
+                  crit=({'Application' : {'log_level' : logging.CRITICAL}},
+                        "set level=CRITICAL"),
+            ))
+
+    def init_foo(self):
+        self.foo = Foo(parent=self)
+
+    def init_bar(self):
+        self.bar = Bar(parent=self)
+
+
+class TestApplication(TestCase):
+
+    def test_log(self):
+        stream = StringIO()
+        app = MyApp(log_level=logging.INFO)
+        handler = logging.StreamHandler(stream)
+        # trigger reconstruction of the log formatter
+        app.log.handlers = [handler]
+        app.log_format = "%(message)s"
+        app.log_datefmt = "%Y-%m-%d %H:%M"
+        app.log.info("hello")
+        assert "hello" in stream.getvalue()
+
+    def test_basic(self):
+        app = MyApp()
+        self.assertEqual(app.name, u'myapp')
+        self.assertEqual(app.running, False)
+        self.assertEqual(app.classes, [MyApp,Bar,Foo])
+        self.assertEqual(app.config_file, u'')
+
+    def test_config(self):
+        app = MyApp()
+        app.parse_command_line(["--i=10","--Foo.j=10","--enabled=False","--log-level=50"])
+        config = app.config
+        self.assertEqual(config.Foo.i, 10)
+        self.assertEqual(config.Foo.j, 10)
+        self.assertEqual(config.Bar.enabled, False)
+        self.assertEqual(config.MyApp.log_level,50)
+
+    def test_config_propagation(self):
+        app = MyApp()
+        app.parse_command_line(["--i=10","--Foo.j=10","--enabled=False","--log-level=50"])
+        app.init_foo()
+        app.init_bar()
+        self.assertEqual(app.foo.i, 10)
+        self.assertEqual(app.foo.j, 10)
+        self.assertEqual(app.bar.enabled, False)
+
+    def test_cli_priority(self):
+        """Test that loading config files does not override CLI options"""
+        name = 'config.py'
+        class TestApp(Application):
+            value = Unicode().tag(config=True)
+            config_file_loaded = Bool().tag(config=True)
+            aliases = {'v': 'TestApp.value'}
+        app = TestApp()
+        with TemporaryDirectory() as td:
+            config_file = pjoin(td, name)
+            with open(config_file, 'w') as f:
+                f.writelines([
+                    "c.TestApp.value = 'config file'\n",
+                    "c.TestApp.config_file_loaded = True\n"
+                ])
+
+            app.parse_command_line(['--v=cli'])
+            assert 'value' in app.config.TestApp
+            assert app.config.TestApp.value == 'cli'
+            assert app.value == 'cli'
+
+            app.load_config_file(name, path=[td])
+            assert app.config_file_loaded
+            assert app.config.TestApp.value == 'cli'
+            assert app.value == 'cli'
+
+    def test_ipython_cli_priority(self):
+        # this test is almost entirely redundant with above,
+        # but we can keep it around in case of subtle issues creeping into
+        # the exact sequence IPython follows.
+        name = 'config.py'
+        class TestApp(Application):
+            value = Unicode().tag(config=True)
+            config_file_loaded = Bool().tag(config=True)
+            aliases = {'v': 'TestApp.value'}
+        app = TestApp()
+        with TemporaryDirectory() as td:
+            config_file = pjoin(td, name)
+            with open(config_file, 'w') as f:
+                f.writelines([
+                    "c.TestApp.value = 'config file'\n",
+                    "c.TestApp.config_file_loaded = True\n"
+                ])
+            # follow IPython's config-loading sequence to ensure CLI priority is preserved
+            app.parse_command_line(['--v=cli'])
+            # this is where IPython makes a mistake:
+            # it assumes app.config will not be modified,
+            # and storing a reference is storing a copy
+            cli_config = app.config
+            assert 'value' in app.config.TestApp
+            assert app.config.TestApp.value == 'cli'
+            assert app.value == 'cli'
+            app.load_config_file(name, path=[td])
+            assert app.config_file_loaded
+            # enforce cl-opts override config file opts:
+            # this is where IPython makes a mistake: it assumes
+            # that cl_config is a different object, but it isn't.
+            app.update_config(cli_config)
+            assert app.config.TestApp.value == 'cli'
+            assert app.value == 'cli'
+
+    def test_flags(self):
+        app = MyApp()
+        app.parse_command_line(["--disable"])
+        app.init_bar()
+        self.assertEqual(app.bar.enabled, False)
+        app.parse_command_line(["--enable"])
+        app.init_bar()
+        self.assertEqual(app.bar.enabled, True)
+
+    def test_aliases(self):
+        app = MyApp()
+        app.parse_command_line(["--i=5", "--j=10"])
+        app.init_foo()
+        self.assertEqual(app.foo.i, 5)
+        app.init_foo()
+        self.assertEqual(app.foo.j, 10)
+
+    def test_flag_clobber(self):
+        """test that setting flags doesn't clobber existing settings"""
+        app = MyApp()
+        app.parse_command_line(["--Bar.b=5", "--disable"])
+        app.init_bar()
+        self.assertEqual(app.bar.enabled, False)
+        self.assertEqual(app.bar.b, 5)
+        app.parse_command_line(["--enable", "--Bar.b=10"])
+        app.init_bar()
+        self.assertEqual(app.bar.enabled, True)
+        self.assertEqual(app.bar.b, 10)
+
+    def test_warn_autocorrect(self):
+        stream = StringIO()
+        app = MyApp(log_level=logging.INFO)
+        app.log.handlers = [logging.StreamHandler(stream)]
+
+        cfg = Config()
+        cfg.MyApp.warn_typo = "WOOOO"
+        app.config = cfg
+
+        self.assertIn("warn_typo", stream.getvalue())
+        self.assertIn("warn_tpyo", stream.getvalue())
+
+
+    def test_flatten_flags(self):
+        cfg = Config()
+        cfg.MyApp.log_level = logging.WARN
+        app = MyApp()
+        app.update_config(cfg)
+        self.assertEqual(app.log_level, logging.WARN)
+        self.assertEqual(app.config.MyApp.log_level, logging.WARN)
+        app.initialize(["--crit"])
+        self.assertEqual(app.log_level, logging.CRITICAL)
+        # this would be app.config.Application.log_level if it failed:
+        self.assertEqual(app.config.MyApp.log_level, logging.CRITICAL)
+
+    def test_flatten_aliases(self):
+        cfg = Config()
+        cfg.MyApp.log_level = logging.WARN
+        app = MyApp()
+        app.update_config(cfg)
+        self.assertEqual(app.log_level, logging.WARN)
+        self.assertEqual(app.config.MyApp.log_level, logging.WARN)
+        app.initialize(["--log-level", "CRITICAL"])
+        self.assertEqual(app.log_level, logging.CRITICAL)
+        # this would be app.config.Application.log_level if it failed:
+        self.assertEqual(app.config.MyApp.log_level, "CRITICAL")
+
+    def test_extra_args(self):
+        app = MyApp()
+        app.parse_command_line(["--Bar.b=5", 'extra', "--disable", 'args'])
+        app.init_bar()
+        self.assertEqual(app.bar.enabled, False)
+        self.assertEqual(app.bar.b, 5)
+        self.assertEqual(app.extra_args, ['extra', 'args'])
+        app = MyApp()
+        app.parse_command_line(["--Bar.b=5", '--', 'extra', "--disable", 'args'])
+        app.init_bar()
+        self.assertEqual(app.bar.enabled, True)
+        self.assertEqual(app.bar.b, 5)
+        self.assertEqual(app.extra_args, ['extra', '--disable', 'args'])
+
+    def test_unicode_argv(self):
+        app = MyApp()
+        app.parse_command_line(['ünîcødé'])
+
+    def test_document_config_option(self):
+        app = MyApp()
+        app.document_config_options()
+
+    def test_generate_config_file(self):
+        app = MyApp()
+        assert 'The integer b.' in app.generate_config_file()
+
+    def test_generate_config_file_classes_to_include(self):
+        class NoTraits(Foo, Bar):
+            pass
+
+        app = MyApp()
+        app.classes.append(NoTraits)
+        conf_txt = app.generate_config_file()
+        self.assertIn('The integer b.', conf_txt)
+        self.assertIn('# Bar(Configurable)', conf_txt)
+        self.assertIn('# Foo(Configurable)', conf_txt)
+        self.assertNotIn('# Configurable', conf_txt)
+        self.assertIn('# NoTraits(Foo,Bar)', conf_txt)
+
+    def test_multi_file(self):
+        app = MyApp()
+        app.log = logging.getLogger()
+        name = 'config.py'
+        with TemporaryDirectory('_1') as td1:
+            with open(pjoin(td1, name), 'w') as f1:
+                f1.write("get_config().MyApp.Bar.b = 1")
+            with TemporaryDirectory('_2') as td2:
+                with open(pjoin(td2, name), 'w') as f2:
+                    f2.write("get_config().MyApp.Bar.b = 2")
+                app.load_config_file(name, path=[td2, td1])
+                app.init_bar()
+                self.assertEqual(app.bar.b, 2)
+                app.load_config_file(name, path=[td1, td2])
+                app.init_bar()
+                self.assertEqual(app.bar.b, 1)
+
+    @mark.skipif(not hasattr(TestCase, 'assertLogs'), reason='requires TestCase.assertLogs')
+    def test_log_collisions(self):
+        app = MyApp()
+        app.log = logging.getLogger()
+        app.log.setLevel(logging.INFO)
+        name = 'config'
+        with TemporaryDirectory('_1') as td:
+            with open(pjoin(td, name + '.py'), 'w') as f:
+                f.write("get_config().Bar.b = 1")
+            with open(pjoin(td, name + '.json'), 'w') as f:
+                json.dump({
+                    'Bar': {
+                        'b': 2
+                    }
+                }, f)
+            with self.assertLogs(app.log, logging.WARNING) as captured:
+                app.load_config_file(name, path=[td])
+                app.init_bar()
+        assert app.bar.b == 2
+        output = '\n'.join(captured.output)
+        assert 'Collision' in output
+        assert '1 ignored, using 2' in output
+        assert pjoin(td, name + '.py') in output
+        assert pjoin(td, name + '.json') in output
+
+    @mark.skipif(not hasattr(TestCase, 'assertLogs'), reason='requires TestCase.assertLogs')
+    def test_log_bad_config(self):
+        app = MyApp()
+        app.log = logging.getLogger()
+        name = 'config.py'
+        with TemporaryDirectory() as td:
+            with open(pjoin(td, name), 'w') as f:
+                f.write("syntax error()")
+            with self.assertLogs(app.log, logging.ERROR) as captured:
+                app.load_config_file(name, path=[td])
+        output = '\n'.join(captured.output)
+        self.assertIn('SyntaxError', output)
+
+    def test_raise_on_bad_config(self):
+        app = MyApp()
+        app.raise_config_file_errors = True
+        app.log = logging.getLogger()
+        name = 'config.py'
+        with TemporaryDirectory() as td:
+            with open(pjoin(td, name), 'w') as f:
+                f.write("syntax error()")
+            with self.assertRaises(SyntaxError):
+                app.load_config_file(name, path=[td])
+
+    def test_loaded_config_files(self):
+        app = MyApp()
+        app.log = logging.getLogger()
+        name = 'config.py'
+        with TemporaryDirectory('_1') as td1:
+            config_file = pjoin(td1, name)
+            with open(config_file, 'w') as f:
+                f.writelines([
+                    "c.MyApp.running = True\n"
+                ])
+
+            app.load_config_file(name, path=[td1])
+            self.assertEqual(len(app.loaded_config_files), 1)
+            self.assertEquals(app.loaded_config_files[0], config_file)
+
+            app.start()
+            self.assertEqual(app.running, True)
+
+            # emulate an app that allows dynamic updates and update config file
+            with open(config_file, 'w') as f:
+                f.writelines([
+                    "c.MyApp.running = False\n"
+                ])
+
+            # reload and verify update, and that loaded_configs was not increased
+            app.load_config_file(name, path=[td1])
+            self.assertEqual(len(app.loaded_config_files), 1)
+            self.assertEqual(app.running, False)
+
+            # Attempt to update, ensure error...
+            with self.assertRaises(AttributeError):
+                app.loaded_config_files = "/foo"
+
+            # ensure it can't be udpated via append
+            app.loaded_config_files.append("/bar")
+            self.assertEqual(len(app.loaded_config_files), 1)
+
+            # repeat to ensure no unexpected changes occurred
+            app.load_config_file(name, path=[td1])
+            self.assertEqual(len(app.loaded_config_files), 1)
+            self.assertEqual(app.running, False)
+
+
+class DeprecatedApp(Application):
+    override_called = False
+    parent_called = False
+    def _config_changed(self, name, old, new):
+        self.override_called = True
+        def _capture(*args):
+            self.parent_called = True
+        with mock.patch.object(self.log, 'debug', _capture):
+            super(DeprecatedApp, self)._config_changed(name, old, new)
+
+
+def test_deprecated_notifier():
+    app = DeprecatedApp()
+    assert not app.override_called
+    assert not app.parent_called
+    app.config = Config({'A': {'b': 'c'}})
+    assert app.override_called
+    assert app.parent_called
+
+
+def test_help_output():
+    check_help_output(__name__)
+    check_help_all_output(__name__)
+
+if __name__ == '__main__':
+    # for test_help_output:
+    MyApp.launch_instance()

venv/Lib/site-packages/traitlets/config/tests/test_configurable.py

@@ -0,0 +1,459 @@
+# encoding: utf-8
+"""Tests for traitlets.config.configurable"""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+import logging
+from unittest import TestCase
+
+from pytest import mark
+
+from traitlets.config.configurable import (
+    Configurable,
+    LoggingConfigurable,
+    SingletonConfigurable,
+)
+
+from traitlets.traitlets import (
+    Integer, Float, Unicode, List, Dict, Set,
+    _deprecations_shown,
+)
+
+from traitlets.config.loader import Config
+from six import PY3
+
+from ...tests._warnings import expected_warnings
+
+class MyConfigurable(Configurable):
+    a = Integer(1, help="The integer a.").tag(config=True)
+    b = Float(1.0, help="The integer b.").tag(config=True)
+    c = Unicode('no config')
+
+
+mc_help=u"""MyConfigurable options
+----------------------
+--MyConfigurable.a=<Integer>
+    Default: 1
+    The integer a.
+--MyConfigurable.b=<Float>
+    Default: 1.0
+    The integer b."""
+
+mc_help_inst=u"""MyConfigurable options
+----------------------
+--MyConfigurable.a=<Integer>
+    Current: 5
+    The integer a.
+--MyConfigurable.b=<Float>
+    Current: 4.0
+    The integer b."""
+
+# On Python 3, the Integer trait is a synonym for Int
+if PY3:
+    mc_help = mc_help.replace(u"<Integer>", u"<Int>")
+    mc_help_inst = mc_help_inst.replace(u"<Integer>", u"<Int>")
+
+class Foo(Configurable):
+    a = Integer(0, help="The integer a.").tag(config=True)
+    b = Unicode('nope').tag(config=True)
+
+
+class Bar(Foo):
+    b = Unicode('gotit', help="The string b.").tag(config=False)
+    c = Float(help="The string c.").tag(config=True)
+
+
+class TestConfigurable(TestCase):
+
+    def test_default(self):
+        c1 = Configurable()
+        c2 = Configurable(config=c1.config)
+        c3 = Configurable(config=c2.config)
+        self.assertEqual(c1.config, c2.config)
+        self.assertEqual(c2.config, c3.config)
+
+    def test_custom(self):
+        config = Config()
+        config.foo = 'foo'
+        config.bar = 'bar'
+        c1 = Configurable(config=config)
+        c2 = Configurable(config=c1.config)
+        c3 = Configurable(config=c2.config)
+        self.assertEqual(c1.config, config)
+        self.assertEqual(c2.config, config)
+        self.assertEqual(c3.config, config)
+        # Test that copies are not made
+        self.assertTrue(c1.config is config)
+        self.assertTrue(c2.config is config)
+        self.assertTrue(c3.config is config)
+        self.assertTrue(c1.config is c2.config)
+        self.assertTrue(c2.config is c3.config)
+        
+    def test_inheritance(self):
+        config = Config()
+        config.MyConfigurable.a = 2
+        config.MyConfigurable.b = 2.0
+        c1 = MyConfigurable(config=config)
+        c2 = MyConfigurable(config=c1.config)
+        self.assertEqual(c1.a, config.MyConfigurable.a)
+        self.assertEqual(c1.b, config.MyConfigurable.b)
+        self.assertEqual(c2.a, config.MyConfigurable.a)
+        self.assertEqual(c2.b, config.MyConfigurable.b)
+
+    def test_parent(self):
+        config = Config()
+        config.Foo.a = 10
+        config.Foo.b = "wow"
+        config.Bar.b = 'later'
+        config.Bar.c = 100.0
+        f = Foo(config=config)
+        with expected_warnings(['`b` not recognized']):
+            b = Bar(config=f.config)
+        self.assertEqual(f.a, 10)
+        self.assertEqual(f.b, 'wow')
+        self.assertEqual(b.b, 'gotit')
+        self.assertEqual(b.c, 100.0)
+
+    def test_override1(self):
+        config = Config()
+        config.MyConfigurable.a = 2
+        config.MyConfigurable.b = 2.0
+        c = MyConfigurable(a=3, config=config)
+        self.assertEqual(c.a, 3)
+        self.assertEqual(c.b, config.MyConfigurable.b)
+        self.assertEqual(c.c, 'no config')
+
+    def test_override2(self):
+        config = Config()
+        config.Foo.a = 1
+        config.Bar.b = 'or'  # Up above b is config=False, so this won't do it.
+        config.Bar.c = 10.0
+        with expected_warnings(['`b` not recognized']):
+            c = Bar(config=config)
+        self.assertEqual(c.a, config.Foo.a)
+        self.assertEqual(c.b, 'gotit')
+        self.assertEqual(c.c, config.Bar.c)
+        with expected_warnings(['`b` not recognized']):
+            c = Bar(a=2, b='and', c=20.0, config=config)
+        self.assertEqual(c.a, 2)
+        self.assertEqual(c.b, 'and')
+        self.assertEqual(c.c, 20.0)
+
+    def test_help(self):
+        self.assertEqual(MyConfigurable.class_get_help(), mc_help)
+
+    def test_help_inst(self):
+        inst = MyConfigurable(a=5, b=4)
+        self.assertEqual(MyConfigurable.class_get_help(inst), mc_help_inst)
+
+
+class TestSingletonConfigurable(TestCase):
+
+    def test_instance(self):
+        class Foo(SingletonConfigurable): pass
+        self.assertEqual(Foo.initialized(), False)
+        foo = Foo.instance()
+        self.assertEqual(Foo.initialized(), True)
+        self.assertEqual(foo, Foo.instance())
+        self.assertEqual(SingletonConfigurable._instance, None)
+
+    def test_inheritance(self):
+        class Bar(SingletonConfigurable): pass
+        class Bam(Bar): pass
+        self.assertEqual(Bar.initialized(), False)
+        self.assertEqual(Bam.initialized(), False)
+        bam = Bam.instance()
+        bam == Bar.instance()
+        self.assertEqual(Bar.initialized(), True)
+        self.assertEqual(Bam.initialized(), True)
+        self.assertEqual(bam, Bam._instance)
+        self.assertEqual(bam, Bar._instance)
+        self.assertEqual(SingletonConfigurable._instance, None)
+
+
+class MyParent(Configurable):
+    pass
+
+class MyParent2(MyParent):
+    pass
+
+class TestParentConfigurable(TestCase):
+    
+    def test_parent_config(self):
+        cfg = Config({
+            'MyParent' : {
+                'MyConfigurable' : {
+                    'b' : 2.0,
+                }
+            }
+        })
+        parent = MyParent(config=cfg)
+        myc = MyConfigurable(parent=parent)
+        self.assertEqual(myc.b, parent.config.MyParent.MyConfigurable.b)
+
+    def test_parent_inheritance(self):
+        cfg = Config({
+            'MyParent' : {
+                'MyConfigurable' : {
+                    'b' : 2.0,
+                }
+            }
+        })
+        parent = MyParent2(config=cfg)
+        myc = MyConfigurable(parent=parent)
+        self.assertEqual(myc.b, parent.config.MyParent.MyConfigurable.b)
+
+    def test_multi_parent(self):
+        cfg = Config({
+            'MyParent2' : {
+                'MyParent' : {
+                    'MyConfigurable' : {
+                        'b' : 2.0,
+                    }
+                },
+                # this one shouldn't count
+                'MyConfigurable' : {
+                    'b' : 3.0,
+                },
+            }
+        })
+        parent2 = MyParent2(config=cfg)
+        parent = MyParent(parent=parent2)
+        myc = MyConfigurable(parent=parent)
+        self.assertEqual(myc.b, parent.config.MyParent2.MyParent.MyConfigurable.b)
+
+    def test_parent_priority(self):
+        cfg = Config({
+            'MyConfigurable' : {
+                'b' : 2.0,
+            },
+            'MyParent' : {
+                'MyConfigurable' : {
+                    'b' : 3.0,
+                }
+            },
+            'MyParent2' : {
+                'MyConfigurable' : {
+                    'b' : 4.0,
+                }
+            }
+        })
+        parent = MyParent2(config=cfg)
+        myc = MyConfigurable(parent=parent)
+        self.assertEqual(myc.b, parent.config.MyParent2.MyConfigurable.b)
+
+    def test_multi_parent_priority(self):
+        cfg = Config({
+            'MyConfigurable' : {
+                'b' : 2.0,
+            },
+            'MyParent' : {
+                'MyConfigurable' : {
+                    'b' : 3.0,
+                }
+            },
+            'MyParent2' : {
+                'MyConfigurable' : {
+                    'b' : 4.0,
+                }
+            },
+            'MyParent2' : {
+                'MyParent' : {
+                    'MyConfigurable' : {
+                        'b' : 5.0,
+                    }
+                }
+            }
+        })
+        parent2 = MyParent2(config=cfg)
+        parent = MyParent2(parent=parent2)
+        myc = MyConfigurable(parent=parent)
+        self.assertEqual(myc.b, parent.config.MyParent2.MyParent.MyConfigurable.b)
+
+class Containers(Configurable):
+    lis = List().tag(config=True)
+    def _lis_default(self):
+        return [-1]
+    
+    s = Set().tag(config=True)
+    def _s_default(self):
+        return {'a'}
+    
+    d = Dict().tag(config=True)
+    def _d_default(self):
+        return {'a' : 'b'}
+
+class TestConfigContainers(TestCase):
+    def test_extend(self):
+        c = Config()
+        c.Containers.lis.extend(list(range(5)))
+        obj = Containers(config=c)
+        self.assertEqual(obj.lis, list(range(-1,5)))
+
+    def test_insert(self):
+        c = Config()
+        c.Containers.lis.insert(0, 'a')
+        c.Containers.lis.insert(1, 'b')
+        obj = Containers(config=c)
+        self.assertEqual(obj.lis, ['a', 'b', -1])
+
+    def test_prepend(self):
+        c = Config()
+        c.Containers.lis.prepend([1,2])
+        c.Containers.lis.prepend([2,3])
+        obj = Containers(config=c)
+        self.assertEqual(obj.lis, [2,3,1,2,-1])
+
+    def test_prepend_extend(self):
+        c = Config()
+        c.Containers.lis.prepend([1,2])
+        c.Containers.lis.extend([2,3])
+        obj = Containers(config=c)
+        self.assertEqual(obj.lis, [1,2,-1,2,3])
+
+    def test_append_extend(self):
+        c = Config()
+        c.Containers.lis.append([1,2])
+        c.Containers.lis.extend([2,3])
+        obj = Containers(config=c)
+        self.assertEqual(obj.lis, [-1,[1,2],2,3])
+
+    def test_extend_append(self):
+        c = Config()
+        c.Containers.lis.extend([2,3])
+        c.Containers.lis.append([1,2])
+        obj = Containers(config=c)
+        self.assertEqual(obj.lis, [-1,2,3,[1,2]])
+
+    def test_insert_extend(self):
+        c = Config()
+        c.Containers.lis.insert(0, 1)
+        c.Containers.lis.extend([2,3])
+        obj = Containers(config=c)
+        self.assertEqual(obj.lis, [1,-1,2,3])
+
+    def test_set_update(self):
+        c = Config()
+        c.Containers.s.update({0,1,2})
+        c.Containers.s.update({3})
+        obj = Containers(config=c)
+        self.assertEqual(obj.s, {'a', 0, 1, 2, 3})
+
+    def test_dict_update(self):
+        c = Config()
+        c.Containers.d.update({'c' : 'd'})
+        c.Containers.d.update({'e' : 'f'})
+        obj = Containers(config=c)
+        self.assertEqual(obj.d, {'a':'b', 'c':'d', 'e':'f'})
+    
+    def test_update_twice(self):
+        c = Config()
+        c.MyConfigurable.a = 5
+        m = MyConfigurable(config=c)
+        self.assertEqual(m.a, 5)
+        
+        c2 = Config()
+        c2.MyConfigurable.a = 10
+        m.update_config(c2)
+        self.assertEqual(m.a, 10)
+        
+        c2.MyConfigurable.a = 15
+        m.update_config(c2)
+        self.assertEqual(m.a, 15)
+    
+    def test_update_self(self):
+        """update_config with same config object still triggers config_changed"""
+        c = Config()
+        c.MyConfigurable.a = 5
+        m = MyConfigurable(config=c)
+        self.assertEqual(m.a, 5)
+        c.MyConfigurable.a = 10
+        m.update_config(c)
+        self.assertEqual(m.a, 10)
+    
+    def test_config_default(self):
+        class SomeSingleton(SingletonConfigurable):
+            pass
+
+        class DefaultConfigurable(Configurable):
+            a = Integer().tag(config=True)
+            def _config_default(self):
+                if SomeSingleton.initialized():
+                    return SomeSingleton.instance().config
+                return Config()
+
+        c = Config()
+        c.DefaultConfigurable.a = 5
+
+        d1 = DefaultConfigurable()
+        self.assertEqual(d1.a, 0)
+        
+        single = SomeSingleton.instance(config=c)
+        
+        d2 = DefaultConfigurable()
+        self.assertIs(d2.config, single.config)
+        self.assertEqual(d2.a, 5)
+
+    def test_config_default_deprecated(self):
+        """Make sure configurables work even with the deprecations in traitlets"""
+        class SomeSingleton(SingletonConfigurable):
+            pass
+
+        # reset deprecation limiter
+        _deprecations_shown.clear()
+        with expected_warnings([]):
+            class DefaultConfigurable(Configurable):
+                a = Integer(config=True)
+                def _config_default(self):
+                    if SomeSingleton.initialized():
+                        return SomeSingleton.instance().config
+                    return Config()
+
+        c = Config()
+        c.DefaultConfigurable.a = 5
+
+        d1 = DefaultConfigurable()
+        self.assertEqual(d1.a, 0)
+        
+        single = SomeSingleton.instance(config=c)
+        
+        d2 = DefaultConfigurable()
+        self.assertIs(d2.config, single.config)
+        self.assertEqual(d2.a, 5)
+
+
+class TestLogger(TestCase):
+
+    class A(LoggingConfigurable):
+            foo = Integer(config=True)
+            bar = Integer(config=True)
+            baz = Integer(config=True)
+    
+    @mark.skipif(not hasattr(TestCase, 'assertLogs'), reason='requires TestCase.assertLogs')
+    def test_warn_match(self):
+        logger = logging.getLogger('test_warn_match')
+        cfg = Config({'A': {'bat': 5}})
+        with self.assertLogs(logger, logging.WARNING) as captured:
+            a = TestLogger.A(config=cfg, log=logger)
+        
+        output = '\n'.join(captured.output)
+        self.assertIn('Did you mean one of: `bar, baz`?', output)
+        self.assertIn('Config option `bat` not recognized by `A`.', output)
+
+        cfg = Config({'A': {'fool': 5}})
+        with self.assertLogs(logger, logging.WARNING) as captured:
+            a = TestLogger.A(config=cfg, log=logger)
+        
+        output = '\n'.join(captured.output)
+        self.assertIn('Config option `fool` not recognized by `A`.', output)
+        self.assertIn('Did you mean `foo`?', output)
+
+        cfg = Config({'A': {'totally_wrong': 5}})
+        with self.assertLogs(logger, logging.WARNING) as captured:
+            a = TestLogger.A(config=cfg, log=logger)
+
+        output = '\n'.join(captured.output)
+        self.assertIn('Config option `totally_wrong` not recognized by `A`.', output)
+        self.assertNotIn('Did you mean', output)
+

venv/Lib/site-packages/traitlets/config/tests/test_loader.py

@@ -0,0 +1,453 @@
+# encoding: utf-8
+"""Tests for traitlets.config.loader"""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+import copy
+import logging
+import os
+import pickle
+import sys
+from tempfile import mkstemp
+from unittest import TestCase
+
+from pytest import skip
+
+from traitlets.config.loader import (
+    Config,
+    LazyConfigValue,
+    PyFileConfigLoader,
+    JSONFileConfigLoader,
+    KeyValueConfigLoader,
+    ArgParseConfigLoader,
+    KVArgParseConfigLoader,
+    ConfigError,
+)
+
+
+pyfile = """
+c = get_config()
+c.a=10
+c.b=20
+c.Foo.Bar.value=10
+c.Foo.Bam.value=list(range(10))
+c.D.C.value='hi there'
+"""
+
+json1file = """
+{
+  "version": 1,
+  "a": 10,
+  "b": 20,
+  "Foo": {
+    "Bam": {
+      "value": [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ]
+    },
+    "Bar": {
+      "value": 10
+    }
+  },
+  "D": {
+    "C": {
+      "value": "hi there"
+    }
+  }
+}
+"""
+
+# should not load
+json2file = """
+{
+  "version": 2
+}
+"""
+
+import logging
+log = logging.getLogger('devnull')
+log.setLevel(0)
+
+class TestFileCL(TestCase):
+
+    def _check_conf(self, config):
+        self.assertEqual(config.a, 10)
+        self.assertEqual(config.b, 20)
+        self.assertEqual(config.Foo.Bar.value, 10)
+        self.assertEqual(config.Foo.Bam.value, list(range(10)))
+        self.assertEqual(config.D.C.value, 'hi there')
+
+    def test_python(self):
+        fd, fname = mkstemp('.py')
+        f = os.fdopen(fd, 'w')
+        f.write(pyfile)
+        f.close()
+        # Unlink the file
+        cl = PyFileConfigLoader(fname, log=log)
+        config = cl.load_config()
+        self._check_conf(config)
+
+    def test_json(self):
+        fd, fname = mkstemp('.json')
+        f = os.fdopen(fd, 'w')
+        f.write(json1file)
+        f.close()
+        # Unlink the file
+        cl = JSONFileConfigLoader(fname, log=log)
+        config = cl.load_config()
+        self._check_conf(config)
+
+    def test_context_manager(self):
+
+        fd, fname = mkstemp('.json')
+        f = os.fdopen(fd, 'w')
+        f.write('{}')
+        f.close()
+
+        cl = JSONFileConfigLoader(fname, log=log)
+
+        value = 'context_manager'
+
+        with cl as c:
+            c.MyAttr.value = value
+
+        self.assertEqual(cl.config.MyAttr.value, value)
+
+        # check that another loader does see the change
+        cl2 = JSONFileConfigLoader(fname, log=log)
+        self.assertEqual(cl.config.MyAttr.value, value)
+
+    def test_json_context_bad_write(self):
+        fd, fname = mkstemp('.json')
+        f = os.fdopen(fd, 'w')
+        f.write('{}')
+        f.close()
+        
+        with JSONFileConfigLoader(fname, log=log) as config:
+            config.A.b = 1
+        
+        with self.assertRaises(TypeError):
+            with JSONFileConfigLoader(fname, log=log) as config:
+                config.A.cant_json = lambda x: x
+        
+        loader = JSONFileConfigLoader(fname, log=log)
+        cfg = loader.load_config()
+        assert cfg.A.b == 1
+        assert 'cant_json' not in cfg.A
+
+    def test_collision(self):
+        a = Config()
+        b = Config()
+        self.assertEqual(a.collisions(b), {})
+        a.A.trait1 = 1
+        b.A.trait2 = 2
+        self.assertEqual(a.collisions(b), {})
+        b.A.trait1 = 1
+        self.assertEqual(a.collisions(b), {})
+        b.A.trait1 = 0
+        self.assertEqual(a.collisions(b), {
+            'A': {
+                'trait1': "1 ignored, using 0",
+            }
+        })
+        self.assertEqual(b.collisions(a), {
+            'A': {
+                'trait1': "0 ignored, using 1",
+            }
+        })
+        a.A.trait2 = 3
+        self.assertEqual(b.collisions(a), {
+            'A': {
+                'trait1': "0 ignored, using 1",
+                'trait2': "2 ignored, using 3",
+            }
+        })
+
+    def test_v2raise(self):
+        fd, fname = mkstemp('.json')
+        f = os.fdopen(fd, 'w')
+        f.write(json2file)
+        f.close()
+        # Unlink the file
+        cl = JSONFileConfigLoader(fname, log=log)
+        with self.assertRaises(ValueError):
+            cl.load_config()
+
+
+class MyLoader1(ArgParseConfigLoader):
+    def _add_arguments(self, aliases=None, flags=None):
+        p = self.parser
+        p.add_argument('-f', '--foo', dest='Global.foo', type=str)
+        p.add_argument('-b', dest='MyClass.bar', type=int)
+        p.add_argument('-n', dest='n', action='store_true')
+        p.add_argument('Global.bam', type=str)
+
+class MyLoader2(ArgParseConfigLoader):
+    def _add_arguments(self, aliases=None, flags=None):
+        subparsers = self.parser.add_subparsers(dest='subparser_name')
+        subparser1 = subparsers.add_parser('1')
+        subparser1.add_argument('-x',dest='Global.x')
+        subparser2 = subparsers.add_parser('2')
+        subparser2.add_argument('y')
+
+class TestArgParseCL(TestCase):
+
+    def test_basic(self):
+        cl = MyLoader1()
+        config = cl.load_config('-f hi -b 10 -n wow'.split())
+        self.assertEqual(config.Global.foo, 'hi')
+        self.assertEqual(config.MyClass.bar, 10)
+        self.assertEqual(config.n, True)
+        self.assertEqual(config.Global.bam, 'wow')
+        config = cl.load_config(['wow'])
+        self.assertEqual(list(config.keys()), ['Global'])
+        self.assertEqual(list(config.Global.keys()), ['bam'])
+        self.assertEqual(config.Global.bam, 'wow')
+
+    def test_add_arguments(self):
+        cl = MyLoader2()
+        config = cl.load_config('2 frobble'.split())
+        self.assertEqual(config.subparser_name, '2')
+        self.assertEqual(config.y, 'frobble')
+        config = cl.load_config('1 -x frobble'.split())
+        self.assertEqual(config.subparser_name, '1')
+        self.assertEqual(config.Global.x, 'frobble')
+
+    def test_argv(self):
+        cl = MyLoader1(argv='-f hi -b 10 -n wow'.split())
+        config = cl.load_config()
+        self.assertEqual(config.Global.foo, 'hi')
+        self.assertEqual(config.MyClass.bar, 10)
+        self.assertEqual(config.n, True)
+        self.assertEqual(config.Global.bam, 'wow')
+
+
+class TestKeyValueCL(TestCase):
+    klass = KeyValueConfigLoader
+
+    def test_eval(self):
+        cl = self.klass(log=log)
+        config = cl.load_config('--Class.str_trait=all --Class.int_trait=5 --Class.list_trait=["hello",5]'.split())
+        self.assertEqual(config.Class.str_trait, 'all')
+        self.assertEqual(config.Class.int_trait, 5)
+        self.assertEqual(config.Class.list_trait, ["hello", 5])
+
+    def test_basic(self):
+        cl = self.klass(log=log)
+        argv = [ '--' + s[2:] for s in pyfile.split('\n') if s.startswith('c.') ]
+        print(argv)
+        config = cl.load_config(argv)
+        self.assertEqual(config.a, 10)
+        self.assertEqual(config.b, 20)
+        self.assertEqual(config.Foo.Bar.value, 10)
+        # non-literal expressions are not evaluated
+        self.assertEqual(config.Foo.Bam.value, 'list(range(10))')
+        self.assertEqual(config.D.C.value, 'hi there')
+    
+    def test_expanduser(self):
+        cl = self.klass(log=log)
+        argv = ['--a=~/1/2/3', '--b=~', '--c=~/', '--d="~/"']
+        config = cl.load_config(argv)
+        self.assertEqual(config.a, os.path.expanduser('~/1/2/3'))
+        self.assertEqual(config.b, os.path.expanduser('~'))
+        self.assertEqual(config.c, os.path.expanduser('~/'))
+        self.assertEqual(config.d, '~/')
+    
+    def test_extra_args(self):
+        cl = self.klass(log=log)
+        config = cl.load_config(['--a=5', 'b', '--c=10', 'd'])
+        self.assertEqual(cl.extra_args, ['b', 'd'])
+        self.assertEqual(config.a, 5)
+        self.assertEqual(config.c, 10)
+        config = cl.load_config(['--', '--a=5', '--c=10'])
+        self.assertEqual(cl.extra_args, ['--a=5', '--c=10'])
+    
+    def test_unicode_args(self):
+        cl = self.klass(log=log)
+        argv = [u'--a=épsîlön']
+        config = cl.load_config(argv)
+        self.assertEqual(config.a, u'épsîlön')
+    
+    def test_unicode_bytes_args(self):
+        uarg = u'--a=é'
+        try:
+            barg = uarg.encode(sys.stdin.encoding)
+        except (TypeError, UnicodeEncodeError):
+            raise skip("sys.stdin.encoding can't handle 'é'")
+        
+        cl = self.klass(log=log)
+        config = cl.load_config([barg])
+        self.assertEqual(config.a, u'é')
+    
+    def test_unicode_alias(self):
+        cl = self.klass(log=log)
+        argv = [u'--a=épsîlön']
+        config = cl.load_config(argv, aliases=dict(a='A.a'))
+        self.assertEqual(config.A.a, u'épsîlön')
+
+
+class TestArgParseKVCL(TestKeyValueCL):
+    klass = KVArgParseConfigLoader
+
+    def test_expanduser2(self):
+        cl = self.klass(log=log)
+        argv = ['-a', '~/1/2/3', '--b', "'~/1/2/3'"]
+        config = cl.load_config(argv, aliases=dict(a='A.a', b='A.b'))
+        self.assertEqual(config.A.a, os.path.expanduser('~/1/2/3'))
+        self.assertEqual(config.A.b, '~/1/2/3')
+    
+    def test_eval(self):
+        cl = self.klass(log=log)
+        argv = ['-c', 'a=5']
+        config = cl.load_config(argv, aliases=dict(c='A.c'))
+        self.assertEqual(config.A.c, u"a=5")
+    
+
+class TestConfig(TestCase):
+
+    def test_setget(self):
+        c = Config()
+        c.a = 10
+        self.assertEqual(c.a, 10)
+        self.assertEqual('b' in c, False)
+
+    def test_auto_section(self):
+        c = Config()
+        self.assertNotIn('A', c)
+        assert not c._has_section('A')
+        A = c.A
+        A.foo = 'hi there'
+        self.assertIn('A', c)
+        assert c._has_section('A')
+        self.assertEqual(c.A.foo, 'hi there')
+        del c.A
+        self.assertEqual(c.A, Config())
+
+    def test_merge_doesnt_exist(self):
+        c1 = Config()
+        c2 = Config()
+        c2.bar = 10
+        c2.Foo.bar = 10
+        c1.merge(c2)
+        self.assertEqual(c1.Foo.bar, 10)
+        self.assertEqual(c1.bar, 10)
+        c2.Bar.bar = 10
+        c1.merge(c2)
+        self.assertEqual(c1.Bar.bar, 10)
+
+    def test_merge_exists(self):
+        c1 = Config()
+        c2 = Config()
+        c1.Foo.bar = 10
+        c1.Foo.bam = 30
+        c2.Foo.bar = 20
+        c2.Foo.wow = 40
+        c1.merge(c2)
+        self.assertEqual(c1.Foo.bam, 30)
+        self.assertEqual(c1.Foo.bar, 20)
+        self.assertEqual(c1.Foo.wow, 40)
+        c2.Foo.Bam.bam = 10
+        c1.merge(c2)
+        self.assertEqual(c1.Foo.Bam.bam, 10)
+
+    def test_deepcopy(self):
+        c1 = Config()
+        c1.Foo.bar = 10
+        c1.Foo.bam = 30
+        c1.a = 'asdf'
+        c1.b = range(10)
+        c1.Test.logger = logging.Logger('test')
+        c1.Test.get_logger = logging.getLogger('test')
+        c2 = copy.deepcopy(c1)
+        self.assertEqual(c1, c2)
+        self.assertTrue(c1 is not c2)
+        self.assertTrue(c1.Foo is not c2.Foo)
+        self.assertTrue(c1.Test is not c2.Test)
+        self.assertTrue(c1.Test.logger is c2.Test.logger)
+        self.assertTrue(c1.Test.get_logger is c2.Test.get_logger)
+
+    def test_builtin(self):
+        c1 = Config()
+        c1.format = "json"
+    
+    def test_fromdict(self):
+        c1 = Config({'Foo' : {'bar' : 1}})
+        self.assertEqual(c1.Foo.__class__, Config)
+        self.assertEqual(c1.Foo.bar, 1)
+    
+    def test_fromdictmerge(self):
+        c1 = Config()
+        c2 = Config({'Foo' : {'bar' : 1}})
+        c1.merge(c2)
+        self.assertEqual(c1.Foo.__class__, Config)
+        self.assertEqual(c1.Foo.bar, 1)
+
+    def test_fromdictmerge2(self):
+        c1 = Config({'Foo' : {'baz' : 2}})
+        c2 = Config({'Foo' : {'bar' : 1}})
+        c1.merge(c2)
+        self.assertEqual(c1.Foo.__class__, Config)
+        self.assertEqual(c1.Foo.bar, 1)
+        self.assertEqual(c1.Foo.baz, 2)
+        self.assertNotIn('baz', c2.Foo)
+    
+    def test_contains(self):
+        c1 = Config({'Foo' : {'baz' : 2}})
+        c2 = Config({'Foo' : {'bar' : 1}})
+        self.assertIn('Foo', c1)
+        self.assertIn('Foo.baz', c1)
+        self.assertIn('Foo.bar', c2)
+        self.assertNotIn('Foo.bar', c1)
+    
+    def test_pickle_config(self):
+        cfg = Config()
+        cfg.Foo.bar = 1
+        pcfg = pickle.dumps(cfg)
+        cfg2 = pickle.loads(pcfg)
+        self.assertEqual(cfg2, cfg)
+    
+    def test_getattr_section(self):
+        cfg = Config()
+        self.assertNotIn('Foo', cfg)
+        Foo = cfg.Foo
+        assert isinstance(Foo, Config)
+        self.assertIn('Foo', cfg)
+
+    def test_getitem_section(self):
+        cfg = Config()
+        self.assertNotIn('Foo', cfg)
+        Foo = cfg['Foo']
+        assert isinstance(Foo, Config)
+        self.assertIn('Foo', cfg)
+
+    def test_getattr_not_section(self):
+        cfg = Config()
+        self.assertNotIn('foo', cfg)
+        foo = cfg.foo
+        assert isinstance(foo, LazyConfigValue)
+        self.assertIn('foo', cfg)
+
+    def test_getattr_private_missing(self):
+        cfg = Config()
+        self.assertNotIn('_repr_html_', cfg)
+        with self.assertRaises(AttributeError):
+            _ = cfg._repr_html_
+        self.assertNotIn('_repr_html_', cfg)
+        self.assertEqual(len(cfg), 0)
+
+    def test_getitem_not_section(self):
+        cfg = Config()
+        self.assertNotIn('foo', cfg)
+        foo = cfg['foo']
+        assert isinstance(foo, LazyConfigValue)
+        self.assertIn('foo', cfg)
+    
+    def test_merge_no_copies(self):
+        c = Config()
+        c2 = Config()
+        c2.Foo.trait = []
+        c.merge(c2)
+        c2.Foo.trait.append(1)
+        self.assertIs(c.Foo, c2.Foo)
+        self.assertEqual(c.Foo.trait, [1])
+        self.assertEqual(c2.Foo.trait, [1])
+