code: def world_size(self):
      return 2
  
file_path: pytorch/test/distributed/fsdp/test_distributed_checkpoint.py
imports: import sys
  import tempfile
  import torch
  from torch import distributed
  from torch.distributed.checkpoint import FileSystemReader, FileSystemWriter, load_state_dict, save_state_dict
  from torch.distributed.fsdp import FullyShardedDataParallel, StateDictType
  from torch.distributed.fsdp.fully_sharded_data_parallel import FullyShardedDataParallel
  from torch.distributed.fsdp.wrap import enable_wrap, wrap
  from torch.testing._internal.common_distributed import skip_if_lt_x_gpu
  from torch.testing._internal.common_fsdp import FSDPTest, SkipModel
  from torch.testing._internal.common_utils import instantiate_parametrized_tests, parametrize, run_tests, TEST_WITH_DEV_DBG_ASAN
label_desc: Use image node_id 1 for calling the TestDistributedCheckpoint obj's underlying member method code with example usage: obj.world_size() and returns: int