code: def set_buffer(self, data):
      self.buffer = data
      return self.buffer
  
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 4 for calling the Worker obj's underlying member method code with example usage: obj.set_buffer(data) and returns: self