code: def get_most_relevant_words_for_topic(vocab, rel_mat, topic, n=None):
      
      _check_relevant_words_for_topic_args(vocab, rel_mat, topic)
      return _words_by_score(vocab, rel_mat[topic], least_to_most=False, n=n)
docs: Get words from `vocab` for `topic` ordered by most to least relevance (Sievert and Shirley 2014) using the relevance
      matrix `rel_mat` obtained from `get_topic_word_relevance()`.
      Optionally only return the `n` most relevant words.