code: def higher_is_better(self):
      return {
          "bleurt_max": True,
          "bleurt_acc": True,
          "bleurt_diff": True,
          "bleu_max": True,
          "bleu_acc": True,
          "bleu_diff": True,
          "rouge1_max": True,
          "rouge1_acc": True,
          "rouge1_diff": True,
          "rouge2_max": True,
          "rouge2_acc": True,
          "rouge2_diff": True,
          "rougeL_max": True,
          "rougeL_acc": True,
          "rougeL_diff": True,
      }
  
imports: import numpy
  import sacrebleu
  import datasets
  from rouge_score import rouge_scorer, scoring
  from lm_eval.base import rf, Task
  from lm_eval.metrics import mean
  from lm_eval.utils import bleu, rouge
label_desc: Use image node_id 15 for calling the TruthfulQAGeneration obj's underlying member method code with example usage: obj.higher_is_better() and returns: dict