问云函数实现微信支付退款，证书复制到云函数目录，但是不能读取？

pfx: require('fs').readFileSync('./apiclient_cert.p12'),

提交失败 Error: errCode: -404011 cloud function execution error | errMsg: cloud.callFunction:fail requestID 815b8c67-d25c-11e9-a36e-52540025df0e, cloud function service error code -504002, error message ENOENT: no such file or directory, open './apiclient_cert.p12'; at cloud.callFunction api;