code: def preprocessing_fn(inputs):
      """Transform preprocessing_fn."""
  
      # generate a shared vocabulary.
      _ = tft.vocabulary(
          tf.concat(
              [
                  inputs[features.QUERY_TOKENS].flat_values,
                  inputs[features.DOCUMENT_TOKENS].flat_values,
              ],
              axis=0,
          ),
          vocab_filename="shared_vocab",
      )
      return inputs
  
file_path: tfx/tfx/examples/ranking/ranking_utils.py
imports: import tensorflow
  import tensorflow_ranking
  import tensorflow_transform
  from tfx.examples.ranking import features
  from tfx.examples.ranking import struct2tensor_parsing_utils
  from tfx_bsl.public import tfxio
label_desc: Use image node_id 2 for calling a global function with example usage: preprocessing_fn(inputs) and returns: inputs