申请退款API（支持单品）报错：“invalid  detail参数格式错误”该如何处理

接口URL：

https://api.mch.weixin.qq.com/secapi/pay/refundv2

接口文档地址：

https://pay.weixin.qq.com/wiki/doc/api/danpin.php?chapter=9_103&index=3

问题：

申请退款API（支持单品）报错：“invalid  detail参数格式错误”该如何处理？

请求参数：

<xml>

    <appid>wx355cXXX67063c515</appid>

    <detail>{"goods_detail":[{"goods_id":"10","refund_amount":19600,"refund_quantity":"2","price":9800}]}</detail>

    <mch_id>1560XXX761</mch_id>

    <nonce_str>0o22pS6XXXXGtk9N1QzgXUbMOAgQZmFi</nonce_str>

    <op_user_id>15608XXX61</op_user_id>

    <out_refund_no>20210520XXX2875794</out_refund_no>

    <out_trade_no>202XXX207551914670</out_trade_no>

    <refund_fee>14700</refund_fee>

    <total_fee>14700</total_fee>

    <sign>FA682DXXXD710A3E07A9B25972DEFB7E</sign>

</xml>

返回报错：“invalid  detail参数格式错误”

解决方案：

 <detail>{"goods_detail":[{"goods_id":"10","refund_amount":19600,"refund_quantity":"2","price":9800}]}</detail>

"refund_quantity":"2"改为"refund_quantity":2