code: def test_batch_setitem_by_index():
      a = Batch(torch.tensor(42))
      b = Batch((torch.tensor(42), torch.tensor(21)))
  
      a[0] = torch.tensor(0)
      b[0] = torch.tensor(0)
  
      assert a.atomic
      assert a[0].item() == 0
  
      assert not b.atomic
      assert len(b) == 2
      assert b[0].item() == 0
      assert b[1].item() == 21
  
file_path: pytorch/test/distributed/pipeline/sync/test_microbatch.py
imports: import pytest
  import torch
  import torch.cuda
  from torch.distributed.pipeline.sync.microbatch import Batch, check, gather, scatter
  from torch.testing._internal.common_utils import run_tests
label_desc: Use image node_id 4 for calling a global function with example usage: test_batch_setitem_by_index() without return types