code: def test_cat_to_num_deserialize_to_cat_to_num():
      serialized_block = blocks.serialize(
          blocks.CategoricalToNumerical()
      )
  
      block = blocks.deserialize(serialized_block)
  
      assert isinstance(block, blocks.CategoricalToNumerical)
  
imports: import keras_tuner
  import tensorflow
  from keras_tuner.engine import hyperparameters
  from tensorflow import keras
  from tensorflow import nest
  from autokeras import blocks
  from autokeras import test_utils
label_desc: Use image node_id 18 for calling a global function with example usage: test_cat_to_num_deserialize_to_cat_to_num() without return types