code: def get_or_generate_txt_vocab(data_dir, vocab_filename, vocab_size,
                                filepatterns):
    
    if isinstance(filepatterns, str):
      filepatterns = [filepatterns]
  
    def generate():
      tf.logging.info("Generating vocab from %s", filepatterns)
      for filepattern in filepatterns:
        for filename in tf.gfile.Glob(filepattern):
          with tf.gfile.GFile(filename, mode="r") as source_file:
            for line in source_file:
              yield line.strip()
  
    return get_or_generate_vocab_inner(data_dir, vocab_filename, vocab_size,
                                       generate())
docs: Generate a vocabulary from txt files with example-per-line.