class_docstr: - Use ROUGE-2 as [PaLM 2](https://ai.google/static/documents/palm2techreport.pdf)
  - Use Mecab tokenizer for Japanese eval
code: def _tokenize(self, text, **kwargs):
      encode_fn = self.tokenizer.encode
      if "add_special_tokens" in inspect.getfullargspec(encode_fn).args:
          encode_params = dict(add_special_tokens=False)
      else:
          encode_params = {}
      return encode_fn(text, **encode_params, **kwargs)
  
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 11 for calling the XLSumJa obj's underlying member method code with example usage: obj._tokenize(text) and returns: encode_fn