code: def init_and_run(fn, args, rank, world_size, filename, filename_rpc):
      dist_init(rank, world_size, filename, filename_rpc)
      group = torch.distributed.new_group()
      fn(rank, group, *args)
  
file_path: fairscale/tests/utils/test_reduce_scatter_bucketer.py
imports: import functools
  import itertools
  import sys
  import unittest
  from unittest import mock
  from parameterized import parameterized
  import torch
  from fairscale.fair_dev.testing.testing import dist_init, spawn_for_all_world_sizes
  from fairscale.internal import torch_version
  from fairscale.internal.reduce_scatter_bucketer import ReduceScatterBucketer
label_desc: Use image node_id 3 for calling a global function with example usage: init_and_run(fn, args, rank, world_size, filename, filename_rpc) without return types