code: def __init__(self) -> None:
      self._data: dict[str, io.BytesIO] = {}
      self._lock = threading.Lock()
  
file_path: optuna/tests/artifacts_tests/stubs.py
imports: from __future__ import annotations
  import copy
  import io
  import shutil
  import threading
  from typing import TYPE_CHECKING
  from optuna.artifacts.exceptions import ArtifactNotFound
label_desc: Use image node_id 1 to create a new InMemoryArtifactStore object  with example: obj = InMemoryArtifactStore()