如何在使用whoosh的文档中获得一个术语的tf-idf评分和bm25f评分?

I am using whoosh to index a dataset. I want to retrieve the td-idf score and bm25f score given a term and document? I have seen the scoring.TFIDF() and scoring.TFIDFScorer(). In order to call TFIDFScorer().score() method we should pass a matcher object. Which matcher object should I pass to it. I am using whoosh to index a dataset. I want to