     var alertController: UIAlertController?
 
     /// The `UIWindow` instance that presents the `SirenViewController`.
-    private var updaterWindow: UIWindow {
-        let window = UIWindow(frame: UIScreen.main.bounds)
-        window.windowLevel = UIWindow.Level.alert + 1
-
-        let viewController = SirenViewController()
-        viewController.retainedWindow = window
-
-        window.rootViewController = viewController
-        return window
-    }
+    private let updaterWindow = createWindow()
 
     /// `PresentationManager`'s public initializer.
     ///

    func cleanUp() {
        alertController?.hide(window: updaterWindow)
        alertController?.dismiss(animated: true, completion: nil)
        self.updaterWindow.rootViewController = nil
        self.updaterWindow.resignKey()
        self.updaterWindow.removeFromSuperview()
    }
}


        return action
    }
}

// MARK: - Helpers

private extension PresentationManager {
    static func createWindow() -> UIWindow {
        let window = UIWindow(frame: UIScreen.main.bounds)
        window.windowLevel = UIWindow.Level.alert + 1

        let viewController = SirenViewController()
        viewController.retainedWindow = window

        window.rootViewController = viewController
        return window
    }
}
