     
     // MARK: - Setting attributes on individual items
     
+    /// Set some attributes for a subview.
+    /// @param w the subview's width
+    /// @param h the subview's height
+    /// @param aspectRatio the subview's width/height ratio
     public func setAttributes(item: UIView, w: CGFloat? = nil, h: CGFloat? = nil, aspectRatio: CGFloat? = nil) -> SimpleAutoLayout {
         if let w = w {
             width(item, w)

        return self
    }
    
    public func destroyAllConstraints() -> SimpleAutoLayout {
        guard let constraints = SimpleAutoLayout.sharedConstraintDict[superview] else {
            return self

        view.translatesAutoresizingMaskIntoConstraints = false
    }
    
    /// Get an existing layout constraint
    /// @param item1 first item of the constraint
    /// @param a1 attribute of the first item
    /// @param item2 second item of the constraint
    /// @param a2 attribute of the second item
    public func constraint(item1: UIView, a1: NSLayoutAttribute, item2: UIView? = nil, a2: NSLayoutAttribute = .NotAnAttribute) -> NSLayoutConstraint? {
        for oldConstraint in superview.constraints {
            if item1 === oldConstraint.firstItem as? UIView
