code: def empty_translation(add_nbest: bool = False) -> Translation:
      
      return Translation(target_ids=[],
                         attention_matrix=np.asarray([[0]]),
                         score=-np.inf,
                         nbest_translations=NBestTranslations([], [], []) if add_nbest else None)
docs: Return an empty translation.
  
      :param add_nbest: Include (empty) nbest_translations in the translation object.