code: def world_size(self):
      return 2
  
file_path: pytorch/test/distributed/fsdp/test_fsdp_apply.py
imports: import sys
  import torch
  import torch.distributed
  import torch.nn
  from torch.distributed.fsdp import FullyShardedDataParallel
  from torch.testing._internal.common_distributed import skip_if_lt_x_gpu
  from torch.testing._internal.common_fsdp import CUDAInitMode, FSDPInitMode, FSDPTest, NestedWrappedModule, TransformerWithSharedParams
  from torch.testing._internal.common_utils import run_tests, TEST_WITH_DEV_DBG_ASAN
label_desc: Use image node_id 1 for calling the TestApply obj's underlying member method code with example usage: obj.world_size() and returns: int