class_docstr: Multiwoz Evaluator. Now, we support metrics `'bleu'`
      
code: def span_db(self, bspan, turn_domain):
      return self.reader.bspan_to_DBpointer(bspan, turn_domain)
  
file_path: TextBox/textbox/evaluator/multiwoz_evaluator.py
imports: import json
  from copy import deepcopy
  from .abstract_evaluator import AbstractEvaluator
  from .utils.multiwoz.config import Config
  from .utils.multiwoz.reader import MultiWozReader
  from .utils.multiwoz.eval import MultiWozEvaluator
label_desc: Use image node_id 3 for calling the MultiwozEvaluator obj's underlying member method code with example usage: obj.span_db(bspan, turn_domain) and returns: self