code: def fill_cache(self):
      for obj in self.data_fetch_func():
          self._data[self.key_func(obj)] = obj
  
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 2 for calling the ObjectCache obj's underlying member method code with example usage: obj.fill_cache() without return types