code: def _expand_nbest_translation(translation: Translation) -> List[Translation]:
      
      nbest_list = []  # type = List[Translation]
      for target_ids, attention_matrix, score in zip(translation.nbest_translations.target_ids_list,
                                                     translation.nbest_translations.attention_matrices,
                                                     translation.nbest_translations.scores):
          nbest_list.append(Translation(target_ids, attention_matrix, score, translation.beam_histories,
                                        estimated_reference_length=translation.estimated_reference_length))
  
      return nbest_list
docs: Expand nbest translations in a single Translation object to one Translation
          object per nbest translation.
  
      :param translation: A Translation object.
      :return: A list of Translation objects.