code: def dist_init(rank, world_size, filename):
      dist.init_process_group(
          init_method="file://" + filename,
          backend=dist.Backend.GLOO,
          rank=rank,
          world_size=world_size,
      )
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import json
  import logging
  import os
  import subprocess
  import tempfile
  import unittest
  from pathlib import Path
  import classy_vision.optim
  import torch
  import torch.distributed
  from classy_vision.optim.zero import ZeRO
  from test.generic.config_utils import get_distributed_launch_cmd, get_fast_test_task_config
  from test.generic.optim_test_util import TestOptimizer
label_desc: Use image node_id 1 for calling a global function with example usage: dist_init(rank, world_size, filename) without return types