         return super.shouldAutorotate
     }
     
-    override open var supportedInterfaceOrientations : UIInterfaceOrientationMask {
+    override open var supportedInterfaceOrientations: UIInterfaceOrientationMask {
         if let topViewController = self.topViewController() {
             return topViewController.supportedInterfaceOrientations
         }

    open var leftViewControllerVisible: Bool = false
    open var rightViewControllerVisible: Bool = false
    
    open weak var leftViewController : UIViewController? {
        willSet {
            if let leftViewController = self.leftViewController {
                leftViewController.removeFromParentViewController()

        }
    }
    
    open weak var rightViewController: UIViewController? {
        willSet {
            if let rightViewController = self.rightViewController {
                rightViewController.removeFromParentViewController()
