Swift iCloud keyValue破坏了我的游戏

尝试使用键值对从iCloud检索int。有人能给我解释一下为什么会出现这样的错误：

 '[<NSUbiquitousKeyValueStore 0x170287e40> valueForUndefinedKey:]: this class is not key value coding-compliant for the key current.'

“[valueForUndefinedKey:]：此类不符合当前密钥的键值编码。”

它在我以前的项目中工作得很好

 var iCloudKeyStore: NSUbiquitousKeyValueStore = NSUbiquitousKeyValueStore()

 func loadSavedData() {

    if let cloudCurrent = iCloudKeyStore.value(forKey: "current") as! Int? { /* <-------- Crashes on this line */
        print("Current Level Found From iCloud: \(cloudCurrent)")
        currentLevel = cloudCurrent
    }else{
        print("No Current Level Found")
    }

    if let cloudAchieved = iCloudKeyStore.value(forKey: "achieved") as! Int? {
        print("Current Level Found From iCloud: \(cloudAchieved)")
        levelAchieved = cloudAchieved
    }else{
        print("No Achieved Level Found")
    }

var-iCloudKeyStore:NSUbiquitousKeyValueStore=NSUbiquitousKeyValueStore（）
func loadSavedData（）{
如果让cloudCurrent=iCloudKeyStore.value（forKey:“current”）作为！Int？{/*值（forKey:）用于动态访问对象的实例变量，即键值编码

该对象上没有名为“current”的实例变量。您希望访问存储中存储的值，根据文档，这应该使用对象（forKey:）完成