Add a method called getUniqueItems to the following class that returns all of the unique values of the items variable. If items holds the values [2, 4, 2, 2, 7, 3, 5, 7], the unique values are [2, 4, 7, 3, 5]. In particular, the unique items should be in the same order with duplicates removed class ItemHolder f private List items = new ArrayList(); public List getItems) f return items; public void addItem (Integer item) items.add (item); public List getUniqueItems) //TODO