我在local端 call 雲函數調用database代碼在一開始會報錯 const cloud = require('wx-server-sdk') cloud.init() const db = cloud.database() // 讀到這行會報錯 Error: errCode: -404011 cloud function execution error | errMsg: cloud.callFunction:fail cloud function service error code -504002, error message TypeError: this.realHandler is not a function     at EventHandler.handle (/var/runtime/node8/bootstrap.js:238:34)     at invoke (/var/runtime/node8/bootstrap.js:111:22)     at Timeout.setTimeout [as _onTimeout] (/var/runtime/node8/bootstrap.js:61:9)     at ontimeout (timers.js:475:11)     at tryOnTimeout (timers.js:310:5)     .     .     . 請問有人知道是什麼原因嗎