def _check_mro(Cls, key) -> bool:
    """Helper to check the mro for a class for the given method/attribute name

    :param Cls:  The class to check
    :param key:  The attribute name to check for in the ``__mro__``

    """
    check = any(key in Base.__dict__ for Base in Cls.__mro__ if
                hasattr(Base, '__dict__'))
    return check