code: def _test_multiprocess(self, f, shared_tensors, init_pg, n_output):
      ws = self.world_size
      # file store will delete the test file on destruction
      file = tempfile.NamedTemporaryFile(delete=False)
      ctx = mp.get_context("spawn")
      c2p = ctx.Queue(2)
      p2c = ctx.Queue(2)
      ps = []
      for i in range(ws):
          p = ctx.Process(
              target=f,
              args=(
                  i,
                  file.name,
                  shared_tensors,
                  ws,
                  init_pg,
                  c2p,
                  p2c,
              ),
          )
  
          p.start()
          ps.append(p)
  
      for _ in range(ws * n_output):
          pid, expected, result = c2p.get()
          self.assertEqual(
              expected,
              result,
              msg=f"Expect rank {pid} to receive tensor {expected} but got {result}.",
          )
  
      for _ in range(ws):
          p2c.put(0)
  
      for p in ps:
          p.join(2)
  
imports: import os
  import sys
  import tempfile
  import torch
  import torch.distributed
  import torch.multiprocessing
  from torch.testing._internal.common_distributed import MultiProcessTestCase
  from torch.testing._internal.common_utils import load_tests, NO_MULTIPROCESSING_SPAWN
label_desc: Use image node_id 1 for calling the AbstractProcessGroupShareTensorTest obj's underlying member method code with example usage: obj._test_multiprocess(f, shared_tensors, init_pg, n_output) without return types