https://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/business-capabilities/virtual-payment/ios.htmlhttps://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/business-capabilities/virtual-payment/ios.html

evidence string决策凭据(必填），业务需返回建议退款/拒绝退款的依据，用于退款审计。

请问evidence的具体内容格式是什么样的