def parse_node(self, response, selector):
        """This method must be overriden with your custom spider functionality"""
        if hasattr(self, 'parse_item'):  # backward compatibility
            return self.parse_item(response, selector)
        raise NotImplementedError
This method must be overriden with your custom spider functionality
stackoverflow/venv/lib/python3.6/site-packages/scrapy/spiders/feed.py