         Removes only constraints pertaining to the width or height of this view.
      */
     func removeHeightWidthConstraints() {
-        for constraint in constraints() as! [NSLayoutConstraint] {
+        for constraint in constraints {
             if constraint.firstAttribute == .Width || constraint.secondAttribute == .Width ||
                 constraint.firstAttribute == .Height || constraint.secondAttribute == .Height {
                     removeConstraint(constraint)

    let scrollView: UIScrollView = {
        let scrollView = UIScrollView()
        
        scrollView.setTranslatesAutoresizingMaskIntoConstraints(false)
        scrollView.showsHorizontalScrollIndicator = false
        scrollView.showsVerticalScrollIndicator = false
        scrollView.pagingEnabled = true

     */
    private func updateViewControllers() {
        
        if scrollView.bounds == CGRect.zero {
            return
        }
        
        scrollView.removeConstraints(scrollView.constraints)
        scrollView.subviews.forEach { $0.removeFromSuperview() }
        
        let metrics = ["w": scrollView.bounds.width, "h": scrollView.bounds.height]
        
