docs: def pad_vocabulary(self, vocab, pad):
          """
          Pads vocabulary to a multiple of 'pad' tokens.
  
          :param vocab: list with vocabulary
          :param pad: integer
          """
          vocab_size = len(vocab)
          padded_vocab_size = (vocab_size + pad - 1) // pad * pad
          for i in range(0, padded_vocab_size - vocab_size):
              token = f'madeupword{i:04d}'
              vocab.append(token)
          assert len(vocab) % pad == 0