code: def sector_code(self):
          
          try:
              return self.__dict__["sector_code"]
          except (KeyError, ValueError):
              raise AttributeError(
                  "Instrument(order_book_id={}) has no attribute 'sector_code' ".format(self.order_book_id)
              )
docs: [str] 板块缩写代码，全球通用标准定义（股票专用）