code: def test_cat_to_num_with_img_input_error():
      input_node = ak.ImageInput()
      output_node = ak.CategoricalToNumerical()(input_node)
  
      with pytest.raises(TypeError) as info:
          graph_module.Graph(input_node, outputs=output_node).compile()
  
      assert "CategoricalToNumerical can only be used" in str(
          info.value
      )
  
file_path: autokeras/autokeras/graph_test.py
imports: import os
  import keras_tuner
  import pytest
  import autokeras
  from autokeras import graph
label_desc: Use image node_id 9 for calling a global function with example usage: test_cat_to_num_with_img_input_error() without return types