class_docstr: Preparer for sequence labeling.
class_docstr_tok: ["Preparer","for","sequence","labeling","."]
docstr: Prepare label vocab
docstr_tok: ["Prepare","label","vocab"]
code: def prepare_label_vocab(self, all_labels):
      """Prepare label vocab"""
      for i in range(self.output_num):
          if (
              os.path.exists(self.label_vocab_file_paths[i])
              and self.use_custom_vocab
          ):
              logging.info(
                  "Reuse label vocab file: {}".format(
                      self.label_vocab_file_paths[i]
                  )
              )
          else:
              prepare_vocab(
                  self.label_vocab_file_paths[i],
                  all_labels[i],
                  min_frequency=self.vocab_min_frequency,
                  use_default_dict=True,
              )
              logging.info(
                  "Generate label vocab file: {}".format(
                      self.label_vocab_file_paths[i]
                  )
              )
  
file_path: delta/delta/data/preprocess/text_seq2seq_preparer.py
imports: import os
  from delta import utils
  from absl import logging
  from delta.data.preprocess.base_preparer import TextPreparer
  from delta.data import utils
  from delta.utils.register import registers
  from delta.data.preprocess.utils import prepare_vocab
  from delta.data.preprocess.utils import prepare_vocab_from_config
  from delta.data.preprocess.text_ops import load_textline_dataset
  from delta.data.utils.common_utils import get_file_len
label_desc: Use image node_id 5 for calling the TextS2SPreparer obj's underlying member method code with example usage: obj.prepare_label_vocab(all_labels) without return types