调用视频号小店的增值服务接口 https://api.weixin.qq.com/wxa/servicemarket/service/get_service_buyer?access_token=xxx 入参 {     "appid":"wxa29dccd8aabaadf0",     "service_id": 2816735804764225537 } {     "errcode": 0,     "errmsg": "ok",     "buyer": {         "appid": "wxa29dccd8aabaadf0",         "service_id": 2816735804764225537,         "spec_list": []     } } wxa29dccd8aabaadf0有成功订购记录的 但是返回的spec_list却是空 请问是什么情况呢

https://api.weixin.qq.com/wxa/servicemarket/service/get_service_buyer?access_token=xxx 入参 {     "appid":"wxa29dccd8aabaadf0",     "service_id": 2816735804764225537 } 返回结果 {     "errcode": 0,     "errmsg": "ok",     "buyer": {         "appid": "wxa29dccd8aabaadf0",         "service_id": 2816735804764225537,         "spec_list": []     } } 这个spec_list为什么是空的呢