code: def _build_vocab(filename, vocab_path, vocab_size):
    data = _read_words(filename)
    counter = collections.Counter(data)
    count_pairs = sorted(counter.items(), key=lambda x: (-x[1], x[0]))
    words, _ = list(zip(*count_pairs))
    words = words[:vocab_size]
    with open(vocab_path, "w") as f:
      f.write("\n".join(words))