     viewControllers.append(viewController)
     
     cycleFromViewController(containerView, fromViewController: nil, toViewController: viewControllers[0])
-
   }
   
   func cycleFromViewController(_ containerView: UIView, fromViewController: AnimatableViewController?, toViewController: AnimatableViewController) {

  
  override func viewDidLoad() {
    super.viewDidLoad()
    createChildViewControllers()
    tabBar.selectedItem = tabBar.items?.first
  }
  


private extension ContainerTransitionViewController {
  
  func makeChildViewControllers() {
    var viewController = AnimatableViewController()
    viewController.view.backgroundColor = .blue
    viewController.transitionAnimationType = TransitionAnimationType(string: "Explode")
