def _scrape(self, response, request, spider):
        """Handle the downloaded response or failure through the spider
        callback/errback"""
        assert isinstance(response, (Response, Failure))

        dfd = self._scrape2(response, request, spider) # returns spiders processed output
        dfd.addErrback(self.handle_spider_error, request, response, spider)
        dfd.addCallback(self.handle_spider_output, request, response, spider)
        return dfd
Handle the downloaded response or failure through the spider
        callback/errback
stackoverflow/venv/lib/python3.6/site-packages/scrapy/core/scraper.py