title: How to call UIAccessibilityRequestGuidedAccessSession()
body: <p>I want to create an app that has a button to lock, and another button to unlock.</p>
  
  <p>Lock - This button will lock device. Only this app's screen will show nothing else will be accessible even after restart same screen will show up. Home button, gestures will get disabled similar to single app mode.</p>
  
  <p>Unlock - This will unlock device and switch to normal behavior of device.</p>
  
  <p>Here's what I tried:</p>
  
  <pre><code>@IBAction func lock(sender: UIButton)
  {
      UIAccessibilityRequestGuidedAccessSession(true) {
          success in
          println("\(success)") // success is false
      }
  }
  
  
  @IBAction func unlock(sender: UIButton)
  {
      UIAccessibilityRequestGuidedAccessSession(false) {
          success in
          println("\(success)") // success is false
      }
  }
  </code></pre>
  
  <p>When I lock it and then press the home button, it goes home. Am I doing anything wrong? What can I do to fix it?</p>
  
  <p>P.S. I'm new to <code>swift</code> coming from <code>Objective-c</code></p>