code: def main():
      parser = _get_parser()
      opts, unknown = parser.parse_known_args()
      build_vocab_main(opts)
  
imports: import os
  import copy
  import multiprocessing
  import pyonmttok
  from functools import partial
  from onmt.utils.logging import init_logger, logger
  from onmt.utils.misc import set_random_seed, check_path
  from onmt.utils.parse import ArgumentParser
  from onmt.opts import data_prepare_opts
  from onmt.inputters.text_corpus import build_corpora_iters, get_corpora
  from onmt.inputters.text_utils import process, append_features_to_text
  from onmt.transforms import make_transforms, get_transforms_cls
  from onmt.constants import CorpusName, CorpusTask
  from collections import Counter
label_desc: Use image node_id 9 for calling a global function with example usage: main() without return types