code: def cleanup(self) -> None:
      gc.collect()
      for i in self.tempfile_pool:
          os.unlink(i.name)
  
file_path: optuna/optuna/testing/tempfile_pool.py
imports: from __future__ import annotations
  import atexit
  import gc
  import os
  import tempfile
  from types import TracebackType
  from typing import Any
  from typing import IO
label_desc: Use image node_id 4 for calling the NamedTemporaryFilePool obj's underlying member method code with example usage: obj.cleanup() without return types