code: def empty_module(pipe_class):
      # Empty sequential module is not illegal.
      model = nn.Sequential()
      model = pipe_class(model, [], worker_map=get_worker_map())
  
      assert model(torch.tensor([42])) == torch.tensor([42])
      assert model((torch.tensor([42]),)) == (torch.tensor([42]),)
  
      # But only tensor or tensors is legal in MultiProcessPipe.
  
      with pytest.raises(TypeError):
          model(42)
  
imports: from collections import OrderedDict
  from copy import deepcopy
  import os
  import time
  import pytest
  import torch
  from torch import nn
  from fairscale.fair_dev.testing.testing import get_worker_map, torch_spawn
  from fairscale.internal import torch_version
  from fairscale.nn.model_parallel.initialize import get_pipeline_parallel_group
  from fairscale.nn.pipe import AsyncPipe
  from fairscale.nn.pipe.types import LazyModule
label_desc: Use image node_id 32 for calling a global function with example usage: empty_module(pipe_class) without return types