// MARK: - UIViewControllerAnimatedTransitioning func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? { return DropTransition() } func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? { return DropTransition() } UIViewControllerTransitioningDelegateΛ࣮