code: def test_face_to_edge():
      transform = FaceToEdge()
      assert str(transform) == "FaceToEdge()"
  
      face = torch.tensor([[0, 0], [1, 1], [2, 3]])
      data = Data(face=face, num_nodes=4)
  
      data = transform(data)
      assert len(data) == 2
      assert data.edge_index.tolist() == [
          [0, 0, 0, 1, 1, 1, 2, 2, 3, 3],
          [1, 2, 3, 0, 2, 3, 0, 1, 0, 1],
      ]
      assert data.num_nodes == 4
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_face_to_edge() without return types