云函数事务处理一直400，代码逻辑基本就是文档里的逻辑改了一下。搜了下相关问题这是常见问题了，就不能修复吗？

CloudSDKError: errCode: -1 unknown error | errMsg: document.update:fail Error: 

          400 Bad Request

        ; at document.update api; 

    at returnAsCloudSDKError (/Users/xiaowei.li/work/session_be/node_modules/wx-server-sdk/index.js:6086:16)

    at Object.returnAsFinalCloudSDKError (/Users/xiaowei.li/work/session_be/node_modules/wx-server-sdk/index.js:6100:15)

    at Promise (/Users/xiaowei.li/work/session_be/node_modules/wx-server-sdk/index.js:1323:32)

    at processTicksAndRejections (internal/process/task_queues.js:86:5)

APP-ID : wx0bb950d1046ee296

env-id: session-dev-31c5m