code: def test_mean_subtraction_norm():
      x = torch.randn(6, 16)
      batch = torch.tensor([0, 0, 1, 1, 1, 2])
  
      norm = MeanSubtractionNorm()
      assert str(norm) == "MeanSubtractionNorm()"
  
      if is_full_test():
          torch.jit.script(norm)
  
      out = norm(x)
      assert out.size() == (6, 16)
      assert torch.allclose(out.mean(), torch.tensor(0.0), atol=1e-6)
  
      out = norm(x, batch)
      assert out.size() == (6, 16)
      assert torch.allclose(
          out[0:2].mean(), torch.tensor(0.0), atol=1e-6
      )
      assert torch.allclose(
          out[0:2].mean(), torch.tensor(0.0), atol=1e-6
      )
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_mean_subtraction_norm() without return types