 
   // MARK: Private
 
-  func centerView(view: UIView, onView: UIView) {
+  private func centerView(view: UIView, onView: UIView) {
     onView.addConstraint(NSLayoutConstraint(
       item: view,
       attribute: .centerX,

  }

}

class ButtonsSimpleExampleSwiftViewController: UIViewController {

  let floatingButtonPlusDimension = CGFloat(24)
  
  override func viewDidLoad() {
    super.viewDidLoad()

