code: def add_or_update(self, app_id, value):
          '''
          Adding or updating the evalution.
          :param app_id:  the ID of the post.
          :param value: the evaluation
          :return:  in JSON format.
          '''
          MEvaluation.add_or_update(self.userinfo.uid, app_id, value)
  
          out_dic = {
              'eval0': MEvaluation.app_evaluation_count(app_id, 0),
              'eval1': MEvaluation.app_evaluation_count(app_id, 1)
          }
  
          return json.dump(out_dic, selff add_or_update(self, app_id, value):
          '''
          Adding or updating the evalution.
          :param app_id:  the ID of the post.
          :param value: the evaluation
          :return:  in JSON format.
          '''
          MEvaluation.add_or_update(self.userinfo.uid, app_id, value)
  
          out_dic = {
              'eval0': MEvaluation.app_evaluation_count(app_id, 0),
              'eval1': MEvaluation.app_evaluation_count(app_id, 1)
          }
  
          return json.dump(out_dic, self)
docs: Adding or updating the evalution.
          :param app_id:  the ID of the post.
          :param value: the evaluation
          :return:  in JSON format.