def METHOD_NAME(self):
    feat = make_feature()
    class_id = ClassInferenceTransformer.infer_feature_class_id(
        feat, default_class_id=None)
    self.assertIsNone(class_id)
    class_id = ClassInferenceTransformer.infer_feature_class_id(
        feat, default_class_id=0)
    self.assertEqual(class_id, 0)