   func show(_ viewController: UIViewController,
             at level: SystemViewControllerLevel,
             statusBarState: StatusBarState,
-            completion: ((Void) -> Void)?) {
+            completion: (() -> Void)?) {
     self.statusBarState = statusBarState
     
     if viewController.modalPresentationStyle == .fullScreen {

   
   - parameter viewController: a view controller to dismiss
   */
  public func dismiss(_ viewController: UIViewController, completion: ((Void) -> Void)? = nil) {
    self.viewController.dismissSystemViewController(viewController, completion: {[weak self] in
      guard let this = self else {
        completion?()

  }
  
  /// Dismiss `viewController`
  func dismissSystemViewController(_ viewController: UIViewController, completion: (() -> Void)?) {
    if viewController.modalPresentationStyle == .fullScreen {
      viewController.willMove(toParentViewController: nil)
      removeView(viewController.view)
