class_docstr: Bleu scorer.
class_docstr_tok: ["Bleu","scorer","."]
docstr: return (bleu_tool, len_ratio) pair
docstr_tok: ["return","(","bleu_tool",",","len_ratio",")","pair"]
code: def score_ratio(self, option=None):
      """return (bleu_tool, len_ratio) pair"""
      return (self.fscore(option=option), self.ratio(option=option))
  
imports: import copy
  import math
  from builtins import dict, range
  from collections import defaultdict
label_desc: Use image node_id 5 for calling the BleuScorer obj's underlying member method code with example usage: obj.score_ratio(option) and returns: self,  self