class_docstr: - Use ROUGE-2 as [PaLM 2](https://ai.google/static/documents/palm2techreport.pdf)
  - Use Mecab tokenizer for Japanese eval
code: def doc_to_text(self, doc):
      return f"ニュース記事:{doc['text']}\n要約:"
  
imports: import os
  import inspect
  from lm_eval.utils import rouge2_mecab
  from lm_eval.base import rf, Task
label_desc: Use image node_id 8 for calling the XLSumJa obj's underlying member method code with example usage: obj.doc_to_text(doc) and returns: str, doc, str