def set_label(self, s, label):
        self.state.body_labels[self.bodies[self.index].segment_id] = label
        self.set_index(self.index + 1)
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))