class MyViewController: NSViewController {
  override func prepareForSegue(segue: NSStoryboardSegue, sender: AnyObject?) {
      if segue.identifier == "configured" {
          if let segue = segue as? PresentWithAnimatorSegue, animator = segue.animator as? TransitionAnimator {

              animator.duration = 1
              animator.transition = [.SlideDown/, .Crossfade]
              animator.backgroundColor = NSColor(calibratedRed: 1, green: 0, blue: 0, alpha: 0.5)
              animator.keepOriginalSize = true
              animator.removeFromView = false
          }
      }
  }