code: def test_center():
      transform = Center()
      assert str(transform) == "Center()"
  
      pos = torch.tensor([[0.0, 0.0], [2.0, 0.0], [4.0, 0.0]])
      data = Data(pos=pos)
  
      data = transform(data)
      assert len(data) == 1
      assert data.pos.tolist() == [[-2, 0], [0, 0], [2, 0]]
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_center() without return types