Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/skimage/_shared/version_requirements.py

@@ -0,0 +1,180 @@
+import sys
+
+
+def ensure_python_version(min_version):
+    if not isinstance(min_version, tuple):
+        min_version = (min_version, )
+    if sys.version_info < min_version:
+        # since ensure_python_version is in the critical import path,
+        # we lazy import it.
+        from platform import python_version
+
+        raise ImportError("""
+
+You are running scikit-image on an unsupported version of Python.
+
+Unfortunately, scikit-image 0.15 and above no longer work with your installed
+version of Python (%s).  You therefore have two options: either upgrade to
+Python %s, or install an older version of scikit-image.
+
+For Python 2.7 or Python 3.4, use
+
+ $ pip install 'scikit-image<0.15'
+
+Please also consider updating `pip` and `setuptools`:
+
+ $ pip install pip setuptools --upgrade
+
+Newer versions of these tools avoid installing packages incompatible
+with your version of Python.
+""" % (python_version(), '.'.join([str(v) for v in min_version])))
+
+
+def _check_version(actver, version, cmp_op):
+    """
+    Check version string of an active module against a required version.
+
+    If dev/prerelease tags result in TypeError for string-number comparison,
+    it is assumed that the dependency is satisfied.
+    Users on dev branches are responsible for keeping their own packages up to
+    date.
+
+    Copyright (C) 2013  The IPython Development Team
+
+    Distributed under the terms of the BSD License.
+    """
+    # since version_requirements.py is in the critical import path, we
+    # lazy import it
+    from distutils.version import LooseVersion
+
+    try:
+        if cmp_op == '>':
+            return LooseVersion(actver) > LooseVersion(version)
+        elif cmp_op == '>=':
+            return LooseVersion(actver) >= LooseVersion(version)
+        elif cmp_op == '=':
+            return LooseVersion(actver) == LooseVersion(version)
+        elif cmp_op == '<':
+            return LooseVersion(actver) < LooseVersion(version)
+        else:
+            return False
+    except TypeError:
+        return True
+
+
+def get_module_version(module_name):
+    """Return module version or None if version can't be retrieved."""
+    mod = __import__(module_name,
+                     fromlist=[module_name.rpartition('.')[-1]])
+    return getattr(mod, '__version__', getattr(mod, 'VERSION', None))
+
+
+def is_installed(name, version=None):
+    """Test if *name* is installed.
+
+    Parameters
+    ----------
+    name : str
+        Name of module or "python"
+    version : str, optional
+        Version string to test against.
+        If version is not None, checking version
+        (must have an attribute named '__version__' or 'VERSION')
+        Version may start with =, >=, > or < to specify the exact requirement
+
+    Returns
+    -------
+    out : bool
+        True if `name` is installed matching the optional version.
+
+    Notes
+    -----
+    Original Copyright (C) 2009-2011 Pierre Raybaut
+    Licensed under the terms of the MIT License.
+    """
+    if name.lower() == 'python':
+        actver = sys.version[:6]
+    else:
+        try:
+            actver = get_module_version(name)
+        except ImportError:
+            return False
+    if version is None:
+        return True
+    else:
+        # since version_requirements is in the critical import path,
+        # we lazy import re
+        import re
+
+        match = re.search('[0-9]', version)
+        assert match is not None, "Invalid version number"
+        symb = version[:match.start()]
+        if not symb:
+            symb = '='
+        assert symb in ('>=', '>', '=', '<'),\
+            "Invalid version condition '%s'" % symb
+        version = version[match.start():]
+        return _check_version(actver, version, symb)
+
+
+def require(name, version=None):
+    """Return decorator that forces a requirement for a function or class.
+
+    Parameters
+    ----------
+    name : str
+        Name of module or "python".
+    version : str, optional
+        Version string to test against.
+        If version is not None, checking version
+        (must have an attribute named '__version__' or 'VERSION')
+        Version may start with =, >=, > or < to specify the exact requirement
+
+    Returns
+    -------
+    func : function
+        A decorator that raises an ImportError if a function is run
+        in the absence of the input dependency.
+    """
+    # since version_requirements is in the critical import path, we lazy import
+    # functools
+    import functools
+
+    def decorator(obj):
+        @functools.wraps(obj)
+        def func_wrapped(*args, **kwargs):
+            if is_installed(name, version):
+                return obj(*args, **kwargs)
+            else:
+                msg = '"%s" in "%s" requires "%s'
+                msg = msg % (obj, obj.__module__, name)
+                if not version is None:
+                    msg += " %s" % version
+                raise ImportError(msg + '"')
+        return func_wrapped
+    return decorator
+
+
+def get_module(module_name, version=None):
+    """Return a module object of name *module_name* if installed.
+
+    Parameters
+    ----------
+    module_name : str
+        Name of module.
+    version : str, optional
+        Version string to test against.
+        If version is not None, checking version
+        (must have an attribute named '__version__' or 'VERSION')
+        Version may start with =, >=, > or < to specify the exact requirement
+
+    Returns
+    -------
+    mod : module or None
+        Module if *module_name* is installed matching the optional version
+        or None otherwise.
+    """
+    if not is_installed(module_name, version):
+        return None
+    return __import__(module_name,
+                      fromlist=[module_name.rpartition('.')[-1]])