from collections import UserDict


class MyDict(UserDict, bar='baz'):
    """
    This is a simple extension of the UserDict class showing kwargs failing

    In python3 class definitions support **kwargs see: pep-3115
    https://www.python.org/dev/peps/pep-3115/

    However any class derived from ABCMeta will throw an exception

    """
    pass

# Throws type error on __new__() because UserDict inherits from ABCMeta and
# it does not support **kwargs
dictionary = MyDict()