code: def test_graph_norm():
      torch.manual_seed(42)
      x = torch.randn(200, 16)
      batch = torch.arange(4).view(-1, 1).repeat(1, 50).view(-1)
  
      norm = GraphNorm(16)
      assert str(norm) == "GraphNorm(16)"
  
      if is_full_test():
          torch.jit.script(norm)
  
      out = norm(x)
      assert out.size() == (200, 16)
      assert torch.allclose(out.mean(dim=0), torch.zeros(16), atol=1e-6)
      assert torch.allclose(
          out.std(dim=0, unbiased=False), torch.ones(16), atol=1e-6
      )
  
      out = norm(x, batch)
      assert out.size() == (200, 16)
      assert torch.allclose(
          out[:50].mean(dim=0), torch.zeros(16), atol=1e-6
      )
      assert torch.allclose(
          out[:50].std(dim=0, unbiased=False), torch.ones(16), atol=1e-6
      )
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_graph_norm() without return types