code: def test_pickle_storage() -> None:
      storage = get_storage()
      study_id = storage.create_new_study(
          directions=[StudyDirection.MINIMIZE]
      )
      storage.set_study_system_attr(study_id, "key", "pickle")
  
      restored_storage = pickle.loads(pickle.dumps(storage))
  
      storage_system_attrs = storage.get_study_system_attrs(study_id)
      restored_storage_system_attrs = (
          restored_storage.get_study_system_attrs(study_id)
      )
      assert (
          storage_system_attrs
          == restored_storage_system_attrs
          == {"key": "pickle"}
      )
  
imports: from concurrent.futures import ProcessPoolExecutor
  from concurrent.futures import ThreadPoolExecutor
  import os
  import pickle
  from typing import Sequence
  import numpy
  import pytest
  import optuna
  from optuna.storages import BaseStorage
  from optuna.study import StudyDirection
  from optuna.trial import TrialState
label_desc: Use image node_id 11 for calling a global function with example usage: test_pickle_storage() without return types