class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    var persistentContainer: NSPersistentContainer!

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        let container = NSPersistentContainer(name: "TransformableModel")
        container.loadPersistentStores { (_, error) in
            guard error == nil else { fatalError() }
            self.persistentContainer = container
        }

        return true
    }
}