code: def _VocabFormat(self):
      return "text"
  
imports: import os
  import apache_beam
  import tensorflow
  import tensorflow_transform
  from tensorflow_transform.beam import analyzer_impls
  from tensorflow_transform.beam import impl
  from tensorflow_transform.beam.tft_beam_io import transform_fn_io
  from tensorflow_transform.beam import tft_unit
  from tensorflow_metadata.proto.v0 import schema_pb2
label_desc: Use image node_id 2 for calling the VocabularyIntegrationTest obj's underlying member method code with example usage: obj._VocabFormat() and returns: str