"""
    pies/_utils.py

    Utils internal to the pies library and not meant for direct external usage.

    Copyright (C) 2013  Timothy Edmund Crosley

    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
    documentation files (the "Software"), to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and
    to permit persons to whom the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all copies or
    substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
    TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    OTHER DEALINGS IN THE SOFTWARE.
"""


def with_metaclass(meta, *bases):
    """
        Enables use of meta classes across Python Versions.
        taken from jinja2/_compat.py

        Use it like this::

            class BaseForm(object):
                pass

            class FormType(type):
                pass

            class Form(with_metaclass(FormType, BaseForm)):
                pass
    """
    class metaclass(meta):
        __call__ = type.__call__
        __init__ = type.__init__
        def __new__(cls, name, this_bases, d):
            if this_bases is None:
                return type.__new__(cls, name, (), d)
            return meta(name, bases, d)
    return metaclass('temporary_class', None, {})


def unmodified_isinstance(*bases):
    """
        When called in the form MyOverrideClass(unmodified_isinstance(BuiltInClass))

        it allows calls against passed in built in instances to pass even if there not a subclass
    """
    class UnmodifiedIsInstance(type):
        def __instancecheck__(cls, instance):
            return isinstance(instance, bases)

    return with_metaclass(UnmodifiedIsInstance, *bases)

Add internal utils module