def _extract_class_dict(cls):
    """Retrieve a copy of the dict of a class without the inherited methods"""
    clsdict = dict(cls.__dict__)
    if len(cls.__bases__) == 1:
        inherited_dict = cls.__bases__[0].__dict__
    else:
        inherited_dict = {}
        for base in reversed(cls.__bases__):
            inherited_dict.update(base.__dict__)
    to_remove = []
    for name, value in clsdict.items():
        try:
            base_value = inherited_dict[name]
            if value is base_value:
                to_remove.append(name)
        except KeyError:
            pass
    for name in to_remove:
        clsdict.pop(name)
    return clsdict
