def test_variants_with_empty_value(self):
        c = Cleaver({}, FakeIdentityProvider(), FakeBackend())
        assert tuple(c._parse_variants((('five', 5), ('nothing', None)))) == (
            ('five', 'nothing'),
            (5, None),
            (1, 1)
        )
L{Message.bind} does not mutate the instance it is called on.
dataset/ETHPy150Open ryanpetrello/cleaver/cleaver/tests/test_base.py/TestVariants.test_variants_with_empty_value--crossover with--dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_message.py/MessageTests.test_bindPreservesOriginal