@IBAction func showMenu(_ sender: AnyObject) {
        if let vc = NSStoryboard(name: "Main", bundle:nil).instantiateController(withIdentifier: "MyViewController") as? MyViewController {

            self.mainContentView.subviews.forEach({ $0.removeFromSuperview() })

            self.mainContentView.addSubview(vc.view)
        }
    }