如何更改Realm单例属性值

I have a Realm object:

我有一个Realm对象:

class TransactionDB: Object {

    dynamic var transactionID : Int = -1
    dynamic var registrationPlate : String = ""
    dynamic var locationID : Int = 0
    dynamic var time : String = ""
    dynamic var subscription : String = ""
    dynamic var startTime : NSDate = NSDate() 
    dynamic var endTime : NSDate = NSDate()
    dynamic var status : Int = -2
    dynamic var requestType : Int = -1
    var extensions : List<ExtensionDB> = List<ExtensionDB>()
    dynamic var price : Double = 0
    dynamic var currency : String = ""
    private dynamic var test : Int = 10

    override static func primaryKey() -> String? {
        return "transactionID"
    }

    class var sharedInstance : TransactionDB {
        struct Singleton {
            static let instance = TransactionDB()
        }
        return Singleton.instance
    }

    static func saveOrUpdate {
        // ......
    }
class T