def create_rank_dicts(self, alt_scores):
        """
        Description:
            Takes in the scores of the alternatives in the form alt:score and
            generates the dictionaries mapping alternatives to rankings and
            rankings to alternatives.
        Parameters:
            alt_scores: dictionary of the scores of every alternative
        """
        self.alts_to_ranks = dict()
        cur_score = max(alt_scores.values())
        cur_rank = 0
        self.ranks_to_alts = {cur_rank:[]}
        for i in sorted(alt_scores.keys(), key=lambda x: -alt_scores[x]):
            if alt_scores[i] == cur_score:
                self.ranks_to_alts[cur_rank].append(i)
            elif alt_scores[i] < cur_score:
                cur_rank += 1
                cur_score = alt_scores[i]
                self.ranks_to_alts[cur_rank] = [i]
            self.alts_to_ranks[i] = cur_rank