https://developers.weixin.qq.com/doc/offiaccount/Message_Management/Batch_Sends_and_Originality_Checks.htmlhttps://developers.weixin.qq.com/doc/offiaccount/Getting_Started/Overview.htmlhttps://developers.weixin.qq.com/doc/offiaccount/Getting_Started/Overview.html 图文群发接口 ，如何指定 “合集” ？