code: def _parse_search_results_html(self, doc):
          
          subgroups = []
          soup = bs4.BeautifulSoup(doc, 'lxml')
          ele_divs = soup.select('div.item.prel')
          if not ele_divs:
              return subgroups
          for item in ele_divs:
              ele_a = item.select('p.tt > a')
              if not ele_a:
                  continue
              link = ele_a[0].get('href')
              title = ele_a[0].get_text().strip()
              subgroups.append({
                  'title': title,
                  'link': link,
              })
          return subgroups
docs: parse search result html, return subgroups
          subgroups: [{ 'title': title, 'link': link}]