class_docstr: Attempts to minimize the BLEU score between the current output
  translation and the reference translation.
  
      BLEU score was defined in (BLEU: a Method for Automatic Evaluation of Machine Translation).
  
      `ArxivURL`_
  
  .. _ArxivURL: https://www.aclweb.org/anthology/P02-1040.pdf
  
      This goal function is defined in (It’s Morphin’ Time! Combating Linguistic Discrimination with Inflectional Perturbations).
  
      `ArxivURL2`_
  
  .. _ArxivURL2: https://www.aclweb.org/anthology/2020.acl-main.263
code: def _get_score(self, model_output, _):
      model_output_at = textattack.shared.AttackedText(model_output)
      ground_truth_at = textattack.shared.AttackedText(
          self.ground_truth_output
      )
      bleu_score = get_bleu(model_output_at, ground_truth_at)
      return 1.0 - bleu_score
  
file_path: TextAttack/textattack/goal_functions/text/minimize_bleu.py
imports: import functools
  import nltk
  import textattack
  from .text_to_text_goal_function import TextToTextGoalFunction
label_desc: Use image node_id 4 for calling the MinimizeBleu obj's underlying member method code with example usage: obj._get_score(model_output, _) and returns: unknown