Parameters
        ----------
        term_ranker : TermRanker

        Returns
        -------
        pd.Dataframe

def apply_ranker(self, term_ranker, use_non_text_features):
        '''
        Parameters
        ----------
        term_ranker : TermRanker

        Returns
        -------
        pd.Dataframe
        '''
        if use_non_text_features:
            return term_ranker(self).use_non_text_features().get_ranks()
        return term_ranker(self).get_ranks()