Returns a new collection (of the same class as the receiver) containing selected items from the receiver. The first item in the new collection is the item corresponding to index start in the receiver. Subsequent items in the new collection correspond to those in the receiver, in the same sequence. If you specify the whole number items, the new collection contains only this number of items (or the number of subsequent items in the receiver, if this is less than items). If you do not specify items, the new collection contains all subsequent items of the receiver. The receiver remains unchanged.