code: def world_size(self):
      return 2
  
imports: from copy import deepcopy
  import torch
  import torch.nn
  from torch.distributed._spmd.api import compile
  from torch.distributed._spmd.parallel_mode import DataParallel
  from torch.distributed._tensor import Replicate
  from torch.nn.parallel import DistributedDataParallel
  from torch.testing._internal.common_distributed import skip_if_lt_x_gpu
  from torch.testing._internal.common_utils import run_tests
  from torch.testing._internal.distributed._tensor.common_dtensor import DTensorTestBase, with_comms
label_desc: Use image node_id 1 for calling the TestDataParallel obj's underlying member method code with example usage: obj.world_size() and returns: int