code: def RR_calc(classes, TOP):
      
      try:
          class_number = len(classes)
          result = sum(list(TOP.values()))
          return result / class_number
      except Exception:
          return "None"
docs: Calculate RR (Global performance index).
  
      :param classes: classes
      :type classes : list
      :param TOP: test outcome positive
      :type TOP : dict
      :return: RR as float