def process_page_3(self, response):
        soup = bs(response.m_response.content, 'lxml')
        car_info_list = soup.select('div#a2 ul#viewlist_ul li a.carinfo')
        for car_info in car_info_list:
            url = 'http://www.che168.com' + car_info['href']
            request = Request(url=url, priority=4, callback=self.process_page_4)
            request.meta['province'] = response.request.meta['province']
            request.meta['city'] = response.request.meta['city']
            request.meta['brand'] = response.request.meta['brand']
            request.meta['cars_line'] = response.request.meta['cars_line']
            yield request
        next_page = soup.find(lambda tag: tag.name == 'a' and '下一页' in tag.text)
        if next_page:
            url = 'http://www.che168.com' + next_page['href']
            request = Request(url=url, priority=3, callback=self.process_page_3)
            request.meta['province'] = response.request.meta['province']
            request.meta['city'] = response.request.meta['city']
            request.meta['brand'] = response.request.meta['brand']
            request.meta['cars_line'] = response.request.meta['cars_line']
            yield request