code: def test_data_parallel_multi_gpu():
      with pytest.warns(UserWarning, match="much slower"):
          module = DataParallel(torch.nn.Identity())
      data_list = [Data(x=torch.randn(x, 1)) for x in [2, 3, 10, 4]]
      batches = module.scatter(data_list, device_ids=[0, 1, 0, 1])
      assert len(batches) == 3
  
imports: import pytest
  import torch
  from torch_geometric.data import Data
  from torch_geometric.nn import DataParallel
  from torch_geometric.testing import onlyCUDA
label_desc: Use image node_id 2 for calling a global function with example usage: test_data_parallel_multi_gpu() without return types