Returns an array of index paths representing the supplementary views to remove.
- iOS 7.0+
- tvOS 9.0+
The specific type of supplementary view.
An array of
NSIndex objects indicating the supplementary views you want to remove or an empty array if you do not want to remove any views of the given kind.
The collection view calls this method whenever you delete cells or sections to the collection view. Implementing this method gives your layout object an opportunity to remove any supplementary views that are no longer needed.