TimerService.swift

@objc protocol Timer {
    func scheduleTimer(target:AnyObject, selector: Selector, interval: NSTimeInterval)->String
    func cancelTimer(id:String)
}

@objc class NSTimerService: Timer {
    var timers:[String:NSTimer] = [:]
    
    func scheduleTimer(target:AnyObject, selector: Selector, interval: NSTimeInterval)->String {
        let id = NSUUID().UUIDString
        timers[id] = NSTimer.scheduledTimerWithTimeInterval(interval, target: target, selector: selector, userInfo: nil, repeats: true)
        return id
    }
    
    func cancelTimer(id:String) {
        timers[id]?.invalidate()
    }
    
    deinit {
        println("Timer service destoryed.")
        for t in timers.keys {
            timers[t]?.invalidate()
        }
        timers.removeAll(keepCapacity: false)
    }
    
}

How many stupids can you find in this code, not including the entire concept?