             guard
                 
                 let view:ViewParent = self.view as? ViewParent,
-                let removeView:View = removeController.view as? View
+                let removeView:ViewProtocol = removeController.view as? ViewProtocol
                 
             else
             {

            
            let view:ViewParent = self.view as? ViewParent,
            let currentController:UIViewController = childViewControllers.last,
            let newView:View = controller.view as? View
            
        else
        {

            
            let view:ViewParent = self.view as? ViewParent,
            let currentController:UIViewController = childViewControllers.last,
            let newView:ViewProtocol = controller.view as? ViewProtocol
            
        else
        {
