title: Object X of class Y does not implement methodSignatureForSelector in Swift
body: <p>I have a class Person which is instantiated multiple times.Each person get's their own timer. Upon in my <code>init</code> for <code>Person</code> I call <code>startTimer()</code>. </p>
  
  <pre><code>class Person {
   var timer = NSTimer()
   func startTimer() {
      timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("timerTick"), userInfo: nil, repeats: true)
   }
  
   func timerTick() {
      angerLevel++
      println("Angry! \(angerLevel)")
   }
  ...
  ...
  }
  </code></pre>
  
  <p>So I may have 3 instances of Person in an array of <code>Person[]</code>. I am getting an error: </p>
  
  <pre><code>2014-06-25 13:57:14.956 ThisProgram[3842:148856] *** NSForwarding: warning: object 0x113760048 of class '_TtC11ThisProgram6Person' does not implement methodSignatureForSelector: -- trouble ahead
  </code></pre>
  
  <p>I read elsewhere that I should inherit from <code>NSObject</code> but this is in Swift not Obj-C. The function is within the class so I am not sure what to do. </p>