code: def __call__(self, response, err):
      if response is None and err is None:
          self._callback(None, None)
      else:
          self._callback(MockInferResult(response), err)
  
file_path: towhee/towhee/serve/triton/bls/mock/mock_triton_client.py
imports: from typing import List, Dict
  from towhee.serve.triton.bls.python_backend_wrapper import pb_utils
label_desc: Use image node_id 2 for calling the CallbackWrapper obj's underlying member method code with example usage: obj.__call__(response, err) without return types