def get_score(self, is_fast=True, given_gram=None):
        """
        Get BLEU scores.
        :param is_fast: Fast mode
        :param given_gram: Calculate specific n-gram BLEU score
        """
        if not self.if_use:
            return 0
        if self.is_first:
            self.get_reference()
            self.is_first = False
        if is_fast:
            return self.get_bleu_fast(given_gram)
        return self.get_bleu(given_gram)

        Get BLEU scores.
        :param is_fast: Fast mode
        :param given_gram: Calculate specific n-gram BLEU score
        
metrics/bleu.py