rouge_score.rouge_scorer.RougeScorer
https://github.com/google-research/google-research/blob/c34656f25265e717cc7f051a99185594892fd041/rouge/rouge_scorer.py#L50
#rouge-score
テスト
https://github.com/google-research/google-research/blob/4e9dcd23ab81f6bf3d0f09ba5557e991cd56658d/rouge/rouge_scorer_test.py
BaseScorer インターフェースを実装
https://github.com/google-research/google-research/blob/c34656f25265e717cc7f051a99185594892fd041/rouge/scoring.py#L40-L53
メソッド
score(self, target, prediction)
を持つ
Score(namedtuple)を返す
https://github.com/google-research/google-research/blob/c34656f25265e717cc7f051a99185594892fd041/rouge/scoring.py#L35-L37
score_multiメソッドも持つがこれはBaseScorerインターフェースにはない