code: def concept_names(self):
          
          try:
              return self.__dict__["concept_names"]
          except (KeyError, ValueError):
              raise AttributeError(
                  "Instrument(order_book_id={}) has no attribute 'concept_names' ".format(self.order_book_id)
              )
docs: [str] 概念股分类，例如：’铁路基建’，’基金重仓’等（股票专用）