code: def test_callback_list_without_stateful_callback(tmp_path):
      """If no callbacks within a CallbackList are stateful, then nothing
      should be saved."""
  
      callbacks = CallbackList([Callback(), Callback()])
      callbacks.save_to_dir(str(tmp_path))
  
      assert not list(
          tmp_path.glob(CallbackList.CKPT_FILE_TMPL.format("*"))
      )
      assert not callbacks.can_restore(str(tmp_path))
  
      with pytest.raises(RuntimeError):
          callbacks.restore_from_dir(str(tmp_path))
  
file_path: ray/python/ray/tune/tests/test_callbacks.py
imports: import pytest
  from typing import Dict, Optional
  from ray.tune.callback import Callback, CallbackList
label_desc: Use image node_id 2 for calling a global function with example usage: test_callback_list_without_stateful_callback(tmp_path) without return types