code: def test_half_hop():
      edge_index = torch.tensor(
          [[0, 1, 1, 2, 0, 1, 2], [1, 0, 2, 1, 0, 1, 2]]
      )
      x = torch.tensor(
          [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]],
          dtype=torch.float,
      )
      data = Data(x=x, edge_index=edge_index)
  
      transform = HalfHop()
      assert str(transform) == "HalfHop(alpha=0.5, p=1.0)"
      data = transform(data)
  
      expected_edge_index = [
          [0, 1, 2, 0, 1, 1, 2, 3, 4, 5, 6, 1, 0, 2, 1],
          [0, 1, 2, 3, 4, 5, 6, 1, 0, 2, 1, 3, 4, 5, 6],
      ]
      expected_x = torch.tensor(
          [
              [1, 2, 3, 4],
              [5, 6, 7, 8],
              [9, 10, 11, 12],
              [3, 4, 5, 6],
              [3, 4, 5, 6],
              [7, 8, 9, 10],
              [7, 8, 9, 10],
          ],
          dtype=torch.float,
      )
      assert len(data) == 3
      assert data.num_nodes == 7
      assert data.edge_index.tolist() == expected_edge_index
      assert torch.allclose(data.x, expected_x, atol=1e-4)
      assert data.slow_node_mask.tolist() == [
          False,
          False,
          False,
          True,
          True,
          True,
          True,
      ]
  
      torch.manual_seed(1)
      data = Data(x=x, edge_index=edge_index)
      transform = HalfHop(p=0.5)
      assert str(transform) == "HalfHop(alpha=0.5, p=0.5)"
      data = transform(data)
  
      expected_edge_index = [
          [1, 0, 1, 2, 0, 1, 2, 3, 4, 5, 1, 2, 1],
          [0, 0, 1, 2, 3, 4, 5, 1, 2, 1, 3, 4, 5],
      ]
      expected_x = torch.tensor(
          [
              [1, 2, 3, 4],
              [5, 6, 7, 8],
              [9, 10, 11, 12],
              [3, 4, 5, 6],
              [7, 8, 9, 10],
              [7, 8, 9, 10],
          ],
          dtype=torch.float,
      )
      assert data.num_nodes == 6
      assert data.edge_index.tolist() == expected_edge_index
      assert torch.allclose(data.x, expected_x, atol=1e-4)
      assert data.slow_node_mask.tolist() == [
          False,
          False,
          False,
          True,
          True,
          True,
      ]
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_half_hop() without return types