如何在gensim中获得过滤后的二元文法的分数？

from gensim.models import Phrases
from gensim.models.phrases import Phraser

sentences = [['this', 'is', 'an', 'example', 'sentence'],
             ['another', 'sentence'],
             ['yet', 'another', 'example', 'sentence']]

bigram = Phrases(sentences, min_count=1, threshold=1)

bigram_phraser = Phraser(bigram)

filtered_sentences = [bigram_phraser[sentence] for sentence in sentences]

scores = []
for sentence in filtered_sentences:
    score = 0
    for word in sentence:
        score += bigram.score([word])
    scores.append(score)