code: def test_valid_transformer_size():
      mha = MultiHeadAttention(units=256, num_heads=4)
      assert mha.units == 256
      with pytest.raises(SystemExit):
          MultiHeadAttention(units=50, num_heads=4)
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_valid_transformer_size() without return types