def find_data_handler(self, data):
        try:
            return getattr(data, 'handler')
        except AttributeError:
            try:
                handler = getattr(self, data.handler_key % 'data_%s')
            except AttributeError:
                raise NoDataHandler('No handler defined for Data %s'
                                    % data.handler_key)
            else:
                return handler
dataset/ETHPy150Open lorien/grab/grab/spider/base.py/Spider.find_data_handler/swapped operands of `%`