code: def do_send(self, group_name="default", dst_rank=0):
      col.send(self.buffer, dst_rank, group_name)
      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 12 for calling the Worker obj's underlying member method code with example usage: obj.do_send(group_name, dst_rank) and returns: self