class_docstr: Bleu scorer.
class_docstr_tok: ["Bleu","scorer","."]
code: def reflen(self, option=None):
      self.compute_score(option=option)
      return self._reflen
  
imports: import copy
  import math
  from builtins import dict, range
  from collections import defaultdict
label_desc: Use image node_id 7 for calling the BleuScorer obj's underlying member method code with example usage: obj.reflen(option) and returns: self