对于关键的randomNumber，此类不符合键值编码

Question

我有这个功能：

func processReceivedRandomNumber(randomNumberDetails: RandomNumberDetails) {
    // 1 
    let mutableArray = NSMutableArray(array: orderOfPlayers)
    mutableArray.add(randomNumberDetails)

    // 2
    let sortByRandomNumber = NSSortDescriptor(key: "randomNumber", ascending: false)
    let sortDescriptors = [sortByRandomNumber]
    mutableArray.sort(using: sortDescriptors)

    // 3
    orderOfPlayers = NSArray(array: mutableArray) as! [RandomNumberDetails]

    // 4
    if allRandomNumbersAreReceived() {
        receivedAllRandomNumbers = true
    }
}

我称之为：

processReceivedRandomNumber(randomNumberDetails: RandomNumberDetails(playerId: player, randomNumber: messageRandomNumber.randomNumber))

使用的类：

class RandomNumberDetails: NSObject {
    let playerId: String
    let randomNumber: UInt32

    init(playerId: String, randomNumber: UInt32) {
        self.playerId = playerId
        self.randomNumber = randomNumber
        super.init()
    }

      func isEqual(object: AnyObject?) -> Bool {
        let randomNumberDetails = object as? RandomNumberDetails
        return randomNumberDetails?.playerId == self.playerId
    }
}

我收到此错误消息：

  

此类不是密钥值编码兼容的密钥randomNumber。'

     

***第一次抛出调用堆栈：   （0x1850ff164 0x184348528 0x1850fee2c 0x185ab2434 0x1859f8e20 0x1859f8874 0x1859f861c 0x100f97d90 0x100f9a30c 0x100f9b4a8 0x100f91c3c 0x100f91d8c 0x19ee9baa0 0x19ee9bba8 0x19eea29e0 0x19e62ab1c 0x185afb2e4 0x1850a777c 0x1850a76fc 0x1850a6f84 0x1850a4b5c 0x184fc4c58 0x186e70f84 0x18e71d5c4 0x100f658d8 0x184ae456c）

     

libc ++ abi.dylib：以NSException类型的未捕获异常终止   （lldb）

有什么问题？