code: def _get_process_group_nccl(self):
      store = dist.FileStore(self.file_name, self.world_size)
      dist.init_process_group(
          backend="nccl",
          world_size=self.world_size,
          rank=self.rank,
          store=store,
      )
      return dist.distributed_c10d._get_default_group()
  
imports: import os
  import sys
  import torch
  from torch import nn
  import torch.distributed
  from torch.distributed.algorithms.ddp_comm_hooks import DDPCommHookType, register_ddp_comm_hook
  from torch.nn.parallel import DistributedDataParallel
  from torch.testing._internal.common_distributed import MultiProcessTestCase, requires_nccl, skip_if_lt_x_gpu
  from torch.testing._internal.common_utils import run_tests, TEST_WITH_DEV_DBG_ASAN
label_desc: Use image node_id 3 for calling the DistributedDataParallelCommHookTest obj's underlying member method code with example usage: obj._get_process_group_nccl() and returns: dist