code: def __del__(self):
      self.buffer0 = None
      self.buffer1 = None
      self.list_buffer0 = None
      self.list_buffer1 = None
  
imports: import cupy
  import logging
  import ray
  import ray.util.collective
  from ray.util.collective.types import Backend, ReduceOp
  from ray.util.collective.collective_group.nccl_util import get_num_gpus
  import torch
label_desc: Use image node_id 2 for calling the MultiGPUWorker obj's underlying member method code with example usage: obj.__del__() without return types