code: def close(self) -> None:
      import pickle
  
      os.makedirs(self.workspace, exist_ok=True)
      bin_path = os.path.join(self.workspace, f"{self.metas.name}.bin")
      with open(bin_path, "wb") as f:
          pickle.dump(self._greetings, f)
  
file_path: jina/tests/unit/orchestrate/flow/flow-construct/mwu-encoder/mwu_encoder.py
imports: import os
  from typing import Any
  from jina import Executor, requests
label_desc: Use image node_id 3 for calling the MWUEncoder obj's underlying member method code with example usage: obj.close() without return types