Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/skimage/io/util.py

@@ -0,0 +1,43 @@
+import urllib.parse
+import urllib.request
+from urllib.error import URLError, HTTPError
+
+import os
+import re
+import tempfile
+from contextlib import contextmanager
+
+
+URL_REGEX = re.compile(r'http://|https://|ftp://|file://|file:\\')
+
+
+def is_url(filename):
+    """Return True if string is an http or ftp path."""
+    return (isinstance(filename, str) and
+            URL_REGEX.match(filename) is not None)
+
+
+@contextmanager
+def file_or_url_context(resource_name):
+    """Yield name of file from the given resource (i.e. file or url)."""
+    if is_url(resource_name):
+        url_components = urllib.parse.urlparse(resource_name)
+        _, ext = os.path.splitext(url_components.path)
+        try:
+            with tempfile.NamedTemporaryFile(delete=False, suffix=ext) as f:
+                u = urllib.request.urlopen(resource_name)
+                f.write(u.read())
+            # f must be closed before yielding
+            yield f.name
+        except (URLError, HTTPError):
+            # could not open URL
+            os.remove(f.name)
+            raise
+        except (FileNotFoundError, FileExistsError,
+                PermissionError, BaseException):
+            # could not create temporary file
+            raise
+        else:
+            os.remove(f.name)
+    else:
+        yield resource_name