code: def __init__(
      self,
      main_pool: "ray.actor.ActorHandle",
      sub_pools: Dict[str, "ray.actor.ActorHandle"],
  ):
      self.main_pool = main_pool
      # Hold sub_pool actor handles to avoid gc.
      self.sub_pools = sub_pools
  
file_path: mars/mars/oscar/backends/ray/backend.py
imports: import logging
  from typing import Dict
  from ....utils import lazy_import, Timer
  from ...backend import BaseActorBackend, register_backend
  from ..context import MarsActorContext
  from .driver import RayActorDriver
  from .pool import RayMainPool
  from .utils import process_address_to_placement, get_placement_group
label_desc: Use image node_id 1 to create a new RayPoolHandle object  with example: obj = RayPoolHandle(main_pool, sub_pools)