def get_output_spec(cls, name):
    """ Get named output spec from self or superclass
    """
    klasses = iter(cls.__mro__)
    base = cls
    while base and hasattr(base, '_output_spec_table'):
        if name in base._output_spec_table:
            return base._output_spec_table[name]
        base = klasses.next()
    return None