code: def test_set2set():
      set2set = Set2Set(in_channels=2, processing_steps=1)
      assert str(set2set) == "Set2Set(2, 4)"
  
      N = 4
      x_1, batch_1 = torch.randn(N, 2), torch.zeros(N, dtype=torch.long)
      out_1 = set2set(x_1, batch_1).view(-1)
  
      N = 6
      x_2, batch_2 = torch.randn(N, 2), torch.zeros(N, dtype=torch.long)
      out_2 = set2set(x_2, batch_2).view(-1)
  
      x, batch = torch.cat([x_1, x_2]), torch.cat(
          [batch_1, batch_2 + 1]
      )
      out = set2set(x, batch)
      assert out.size() == (2, 4)
      assert torch.allclose(out_1, out[0])
      assert torch.allclose(out_2, out[1])
  
      x, batch = torch.cat([x_2, x_1]), torch.cat(
          [batch_2, batch_1 + 1]
      )
      out = set2set(x, batch)
      assert out.size() == (2, 4)
      assert torch.allclose(out_1, out[1])
      assert torch.allclose(out_2, out[0])
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_set2set() without return types