报错了，老师求救求救，谢谢了

2023-08-11 22:16:06,826 ERROR 14048  --- [PLAYERS-D03ERHO] - nodejs.TypeError: b.created_at.localeCompare is not a function

    at sort (D:\work\nodejs\starter\app\service\/content.js:18:36)

    at Array.sort (<anonymous>)

    at Function.getContentList (D:\work\nodejs\starter\app\service\/content.js:18:9)

    at D:\work\nodejs\starter\app\api\v1\/content.js:22:23

    at exports.log (D:\work\nodejs\starter\node_modules\lin-mizar\lin\middleware\log.js:15:9)

    at D:\work\nodejs\starter\node_modules\koa-mount\index.js:52:26

    at bodyParser (D:\work\nodejs\starter\node_modules\koa-bodyparser\index.js:78:5)

pid: 14048

hostname: PLAYERS-D03ERHO