code: def __init__(self, service_config: Optional[Dict] = None):
      self._session_refs: Dict[str, mo.ActorRef] = dict()
      self._cluster_api: Optional[ClusterAPI] = None
      self._service_config = service_config or dict()
      self._stored_last_idle_time = None
  
imports: import asyncio
  import functools
  import logging
  import os
  import time
  from typing import Dict, List, Optional
  from ....None import oscar
  from ....utils import to_binary
  from ...cluster import ClusterAPI
  from ...core import NodeRole, create_service_session, destroy_service_session
  from ..core import SessionInfo
label_desc: Use image node_id 1 to create a new SessionManagerActor object from inherited base classes: mo with example: obj = SessionManagerActor(service_config)