code: def test_delete_study() -> None:
      base_storage = RDBStorage("sqlite:///:memory:")
      storage = _CachedStorage(base_storage)
  
      study_id1 = storage.create_new_study(
          directions=[StudyDirection.MINIMIZE]
      )
      trial_id1 = storage.create_new_trial(study_id1)
      storage.set_trial_state_values(
          trial_id1, state=TrialState.COMPLETE
      )
  
      study_id2 = storage.create_new_study(
          directions=[StudyDirection.MINIMIZE]
      )
      trial_id2 = storage.create_new_trial(study_id2)
      storage.set_trial_state_values(
          trial_id2, state=TrialState.COMPLETE
      )
  
      # Update _StudyInfo.finished_trial_ids
      storage._read_trials_from_remote_storage(study_id1)
      storage._read_trials_from_remote_storage(study_id2)
  
      storage.delete_study(study_id1)
      assert storage._get_cached_trial(trial_id1) is None
      assert storage._get_cached_trial(trial_id2) is not None
  
file_path: optuna/tests/storages_tests/test_cached_storage.py
imports: from unittest.mock import patch
  import pytest
  import optuna
  from optuna.storages._cached_storage import _CachedStorage
  from optuna.storages._rdb.storage import RDBStorage
  from optuna.study import StudyDirection
  from optuna.trial import TrialState
label_desc: Use image node_id 5 for calling a global function with example usage: test_delete_study() without return types