code: def extract_answer(self, response, row):
      prompt = row["question"]
      gen = self.process_before_extraction(
          response,
          prompt,
          {choice: row[choice] for choice in self.choices},
      )
      if not isinstance(prompt, str):
          prompt = prompt[0]
      pred = self.extract_choice(
          gen, prompt, [row[choice] for choice in self.choices]
      )
      return pred
  
file_path: BigDL/python/llm/dev/benchmark/ceval/evaluators/qwen.py
imports: import re
  from tqdm import tqdm
  import torch
  from thefuzz import process
  from transformers import AutoTokenizer
  from transformers.generation import GenerationConfig
  from bigdl.llm.transformers import AutoModelForCausalLM
  from evaluators.evaluator import Evaluator
label_desc: Use image node_id 6 for calling the QwenEvaluator obj's underlying member method code with example usage: obj.extract_answer(response, row) and returns: pred