diff --git a/oauth2client/util.py b/oauth2client/util.py
new file mode 100644
index 0000000..bda14c6
--- /dev/null
+++ b/oauth2client/util.py
@@ -0,0 +1,127 @@
+#!/usr/bin/env python
+#
+# Copyright 2010 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""Common utility library."""
+
+__author__ = ['rafek@google.com (Rafe Kaplan)',
+              'guido@google.com (Guido van Rossum)',
+]
+__all__ = [
+  'positional',
+]
+
+import gflags
+import inspect
+import logging
+
+logger = logging.getLogger(__name__)
+
+FLAGS = gflags.FLAGS
+
+gflags.DEFINE_enum('positional_parameters_enforcement', 'WARNING',
+    ['EXCEPTION', 'WARNING', 'IGNORE'],
+    'The action when an oauth2client.util.positional declaration is violated.')
+
+
+def positional(max_positional_args):
+  """A decorator to declare that only the first N arguments my be positional.
+
+  This decorator makes it easy to support Python 3 style key-word only
+  parameters.  For example, in Python 3 it is possible to write:
+
+    def fn(pos1, *, kwonly1=None, kwonly1=None):
+      ...
+
+  All named parameters after * must be a keyword:
+
+    fn(10, 'kw1', 'kw2')  # Raises exception.
+    fn(10, kwonly1='kw1')  # Ok.
+
+  Example:
+    To define a function like above, do:
+
+      @positional(1)
+      def fn(pos1, kwonly1=None, kwonly2=None):
+        ...
+
+    If no default value is provided to a keyword argument, it becomes a required
+    keyword argument:
+
+      @positional(0)
+      def fn(required_kw):
+        ...
+
+    This must be called with the keyword parameter:
+
+      fn()  # Raises exception.
+      fn(10)  # Raises exception.
+      fn(required_kw=10)  # Ok.
+
+    When defining instance or class methods always remember to account for
+    'self' and 'cls':
+
+      class MyClass(object):
+
+        @positional(2)
+        def my_method(self, pos1, kwonly1=None):
+          ...
+
+        @classmethod
+        @positional(2)
+        def my_method(cls, pos1, kwonly1=None):
+          ...
+
+  The positional decorator behavior is controlled by the
+  --positional_parameters_enforcement flag. The flag may be set to 'EXCEPTION',
+  'WARNING' or 'IGNORE' to raise an exception, log a warning, or do nothing,
+  respectively, if a declaration is violated.
+
+  Args:
+    max_positional_arguments: Maximum number of positional arguments.  All
+      parameters after the this index must be keyword only.
+
+  Returns:
+    A decorator that prevents using arguments after max_positional_args from
+    being used as positional parameters.
+
+  Raises:
+    TypeError if a key-word only argument is provided as a positional parameter,
+    but only if the --positional_parameters_enforcement flag is set to
+    'EXCEPTION'.
+  """
+  def positional_decorator(wrapped):
+    def positional_wrapper(*args, **kwargs):
+      if len(args) > max_positional_args:
+        plural_s = ''
+        if max_positional_args != 1:
+          plural_s = 's'
+        message = '%s() takes at most %d positional argument%s (%d given)' % (
+            wrapped.__name__, max_positional_args, plural_s, len(args))
+        if FLAGS.positional_parameters_enforcement == 'EXCEPTION':
+          raise TypeError(message)
+        elif FLAGS.positional_parameters_enforcement == 'WARNING':
+          logger.warning(message)
+        else: # IGNORE
+          pass
+      return wrapped(*args, **kwargs)
+    return positional_wrapper
+
+  if isinstance(max_positional_args, (int, long)):
+    return positional_decorator
+  else:
+    args, _, _, defaults = inspect.getargspec(max_positional_args)
+    return positional(len(args) - len(defaults))(max_positional_args)