class_docstr: A constraint on BLEU score difference.
  
  Args:
      max_bleu_score (int): Maximum BLEU score allowed.
      compare_against_original (bool):  If `True`, compare new `x_adv` against the original `x`.
          Otherwise, compare it against the previous `x_adv`.
class_docstr_tok: ["A","constraint","on","BLEU","score","difference",".","Args",":","max_bleu_score","(","int",")",":","Maximum","BLEU","score","allowed",".","compare_against_original","(","bool",")",":","If","`","True","`",",","compare","new","`","x_adv","`","against","the","original","`","x","`",".","Otherwise",",","compare","it","against","the","previous","`","x_adv","`","."]
code: def __init__(self, max_bleu_score, compare_against_original=True):
      super().__init__(compare_against_original)
      if not isinstance(max_bleu_score, int):
          raise TypeError("max_bleu_score must be an int")
      self.max_bleu_score = max_bleu_score
  
imports: import nltk
  from textattack.constraints import Constraint
label_desc: Use image node_id 1 to create a new BLEU object from inherited base classes: Constraint with example: obj = BLEU(max_bleu_score, compare_against_original)