sqlalchemy如何使用dblink

Question

有个跨数据数查询的语句
select a1.game_name, a1.template_name, a1.visitnum, a1.ip, a3.regnum from

        (select game_name, template_name, count(template_name) as visitnum, count(distinct(ip)) as ip from page_visit_log 
            where logdate >= '%s' and logdate <= '%s' group by game_name, template_name order by visitnum desc) as a1
        left join dblink('%s', 'select id, interface_name from game_game') as a2(id int, interface_name character varying(30)) 
            on a2.interface_name = a1.game_name
        left join dblink('%s', 'select creative, ccgame_id, count (*) as regnum from user_user where reg_date >= \'\'%s\'\' 
            and reg_date <= \'\'%s\'\' group by creative, ccgame_id')
            as a3(creative character varying(30), ccgame_id int, regnum int) on a3.creative=a1.template_name and a3.ccgame_id = a2.id
            

如何写成sqlalchemy的形式，主要这个框架的dblink没用过，请教各位大大