code: def _rouge(self, item):
      predictions, references = zip(*item)
      res = rouge2_mecab(
          refs=references, preds=predictions, tokenizer=self.tokenizer
      )
      return res["rouge2"]
  
imports: import os
  import numpy
  import datasets
  from lm_eval.base import rf, Task
  from lm_eval.metrics import mean
  from lm_eval.utils import rouge2_mecab
label_desc: Use image node_id 12 for calling the Wikilingua obj's underlying member method code with example usage: obj._rouge(item) and returns: res