def get_real_bases(bases):
    """
    Get real bases for types argument.
    >>> get_real_bases(None) #=> (object,)
    >>> get_real_bases(TypeA) #=> (TypeA,)
    >>> get_real_bases([TypeA, TypeB]) #=> (TypeA, TypeB)

    :param bases: type or type sequence
    """
    if bases is None:
        return (object,)
    if isinstance(bases, type):
        bases = (bases,)
    return tuple(bases)