code: def scrape(self, request, response, link_type=None):
          '''Iterate the scrapers, returning the first of the results.'''
          for scraper in self._document_scrapers:
              scrape_result = scraper.scrape(request, response, link_type)
  
              if scrape_result is None:
                  continue
  
              if scrape_result.link_contexts:
                  return scrape_resulf scrape(self, request, response, link_type=None):
          '''Iterate the scrapers, returning the first of the results.'''
          for scraper in self._document_scrapers:
              scrape_result = scraper.scrape(request, response, link_type)
  
              if scrape_result is None:
                  continue
  
              if scrape_result.link_contexts:
                  return scrape_result
docs: Iterate the scrapers, returning the first of the results.