The generated object is one ore more nested CompoundBorders creating a border from the supplied border.
The optional value argument is an array of one or more border objects. If only one border object is passed in then the result of the node is that border. Otherwise the result is one or more nested compound borders containing the borders in an outside to inside order. The compound border representing the innermost border and it's parent compound will be returned.
If the value argument is used the outerBorder: and innerBorder: attribute arguments are prohibited.
Only the simple two border compound can be created via attributes. Both inner: and outer: attributes are required.
compoundBorder() is a leaf node, no child content is allowed.