code: def dummy_tf_models():
      class DummyTFModel(TensorflowModel):
          CONFIGURATIONS = {
              "dummy_tf_model": {
                  "asset": "dummy_tf_model:0.0",
                  "model_settings": {
                      "output_dtypes": {"lambda": np.float32},
                      "output_tensor_mapping": {"lambda": "nothing"},
                      "output_shapes": {"lambda": (3, 2, 1)},
                  },
              }
          }
  
          def _is_empty(self, item):
              if item["input_1"][0, 0, 0] == -1:
                  return True
              return False
  
      class DummyTFModelNoIsEmpty(TensorflowModel):
          CONFIGURATIONS = {
              "dummy_tf_model_no_is_empty": {
                  "asset": "dummy_tf_model:0.0",
                  "model_settings": {
                      "output_dtypes": {"lambda": np.float32},
                      "output_tensor_mapping": {"lambda": "nothing"},
                      "output_shapes": {"lambda": (3, 2, 1)},
                      "tf_model_name": "dummy_tf_model",
                  },
              }
          }
  
      class DummyTFModelAsync(AsyncTensorflowModel):
          CONFIGURATIONS = {
              "dummy_tf_model_async": {
                  "asset": "dummy_tf_model:0.0",
                  "model_settings": {
                      "output_dtypes": {"lambda": np.float32},
                      "output_tensor_mapping": {"lambda": "nothing"},
                      "output_shapes": {"lambda": (3, 2, 1)},
                      "tf_model_name": "dummy_tf_model",
                  },
              }
          }
  
          def _is_empty(self, item):
              if item["input_1"][0, 0, 0] == -1:
                  return True
              return False
  
      return DummyTFModel, DummyTFModelAsync, DummyTFModelNoIsEmpty
  
imports: import os
  import pytest
  import requests
  from modelkit import ModelLibrary, testing
  from modelkit.core.models.tensorflow_model import AsyncTensorflowModel, TensorflowModel, has_tensorflow
  from modelkit.core.settings import LibrarySettings
  from modelkit.testing import tf_serving_fixture
  from modelkit.utils.tensorflow import write_config
  from tests import TEST_DIR
  from tests.conftest import skip_unless
label_desc: Use image node_id 1 for calling a global function with example usage: dummy_tf_models() and returns: DummyTFModel,  DummyTFModelAsync,  DummyTFModelNoIsEmpty, False, False, True, True