code: def world_size(self) -> int:
      return 2
  
file_path: pytorch/torch/testing/_internal/distributed/pipe_with_ddp_test.py
imports: import torch
  import torch.distributed
  from torch import nn
  from torch.nn.parallel import DistributedDataParallel
  from torch.testing._internal.dist_utils import INIT_METHOD_TEMPLATE, dist_init
  from torch.testing._internal.distributed.rpc.rpc_agent_test_fixture import RpcAgentTestFixture
  from torch.testing._internal.common_distributed import requires_gloo, requires_nccl, skip_if_lt_x_gpu, skip_if_rocm
  from torch.distributed.pipeline.sync import Pipe
label_desc: Use image node_id 1 for calling the PipeWithDDPTest obj's underlying member method code with example usage: obj.world_size() and returns: int