code: def __getitem__(self, key):
      if not self._cached:
          self.fill_cache()
          self._cached = True
      return self._data[key]
  
imports: import os
  from collections import defaultdict
  from weakref import WeakValueDictionary
  from sqlalchemy import create_engine
  from sqlalchemy.orm import sessionmaker, scoped_session
  from aim.storage.migrations.utils import upgrade_database
  from aim.storage.structured.sql_engine.factory import ModelMappedFactory
  from aim.storage.types import SafeNone
  from aim.web.configs import AIM_LOG_LEVEL_KEY
label_desc: Use image node_id 6 for calling the ObjectCache obj's underlying member method code with example usage: obj.__getitem__(key) and returns: self