def get_client_by_appid(self, authorizer_appid):
        """
        通过 authorizer_appid 获取 Client 对象

        :params authorizer_appid: 授权公众号appid
        """
        access_token_key = '{0}_access_token'.format(authorizer_appid)
        refresh_token_key = '{0}_refresh_token'.format(authorizer_appid)
        access_token = self.session.get(access_token_key)
        refresh_token = self.session.get(refresh_token_key)
        assert refresh_token

        if not access_token:
            ret = self.refresh_authorizer_token(
                authorizer_appid,
                refresh_token
            )
            access_token = ret['authorizer_access_token']
            refresh_token = ret['authorizer_refresh_token']
            access_token_key = '{0}_access_token'.format(authorizer_appid)
            expires_in = 7200
            if 'expires_in' in ret:
                expires_in = ret['expires_in']
            self.session.set(access_token_key, access_token, expires_in)

        return WeChatComponentClient(
            authorizer_appid,
            self,
            session=self.session
        )