Pop 2 view controllers in Nav Controller in Swift

Question

I have found many ways to pop back 2 UIViewControllers in UINavigationController using Objective-C, however when I try and switch that over to Swift it

Answer 1

 let allViewControllers : [UIViewController] = self.navigationController!.viewControllers as [UIViewController]
        self.navigationController?.popToViewController(allViewControllers[allViewControllers.count-3], animated: true)