code: def test_list_models_legacy(self):
      sys.path.append(
          os.path.abspath(
              "ts/tests/unit_tests/model_service/dummy_model"
          )
      )
      module = importlib.import_module("dummy_model_service")
      classes = list_classes_from_module(module, SingleNodeService)
      assert len(classes) == 1
      assert issubclass(classes[0], SingleNodeService)
  
imports: import importlib
  import inspect
  import os
  import sys
  import types
  from collections import namedtuple
  import mock
  import pytest
  from ts.model_loader import ModelLoaderFactory, TsModelLoader
  from ts.model_service.model_service import SingleNodeService
  from ts.torch_handler.request_envelope.json import JSONEnvelope
  from ts.utils.util import list_classes_from_module
label_desc: Use image node_id 1 for calling the TestListModels obj's underlying member method code with example usage: obj.test_list_models_legacy() without return types