def __init__(self, name, filename=None):
        self.name = name
        super(NamedRequirements, self).__init__(filename=filename)
def test_supertype(self):
        self.assert_(isinstance(None, NullType))
        self.assert_(isinstance(Optional('a'), NullType))
        self.assert_(isinstance(NotPassed, NotPassedType))
        self.assert_(isinstance(NotPassed, NullType))