code: def page_crawled(self, page_resp):
          
          page_text = utils.parse_text(page_resp)
          page_hash = utils.hash_text(''.join(page_text))
          if page_hash not in self.page_cache:
              utils.cache_page(self.page_cache, page_hash, self.args['cache_size'])
              return False
          return True
docs: Check if page has been crawled by hashing its text content.
  
          Add new pages to the page cache.
          Return whether page was found in cache.