def test_does_quack_model_id_negative(self):
     NoModelId = type('InvalidModelId', (BaseValid,), {})
     assert not _ModelIdMixin._does_quack(NoModelId())
 def test_does_quack_model_id_mixin(self):
     ValidModelId = type('ValidModelId', (_ModelIdValid,), {})
     assert _ModelIdMixin._does_quack(ValidModelId())