def _visit_detailpage(self, detailpage_link, referer):
        """访问字幕详情页面，解析出下载页面的地址
        """
        headers = {'Referer': referer}
        res = self.session.get(detailpage_link, headers=headers)
        referer = res.url
        doc = res.content
        result = self._parse_detailpage_html(doc)
        return result, referer