code: def remove(self, artifact_id: str) -> None:
      with self._lock:
          if artifact_id not in self._data:
              raise ArtifactNotFound("not found")
          del self._data[artifact_id]
  
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 4 for calling the InMemoryArtifactStore obj's underlying member method code with example usage: obj.remove(artifact_id) without return types