Implement the stack family instance method flip declared as follows (this is a Stack):/** * Reverses ("flips") {@code this} * * @ updates this * @ensures this = rev (#this) */public void flip(); Implement the sequence family instance method flip declared as follows (this is a sequence ):/** * Reverses ("flips"){@code this}. * *@updates this * @ ensures this = rev(#this) */public void flip (); Provide a second, different implementation of the instance method flip for Sequence. If your first implementation is iterative (i.e., uses a loop), your second one should be recursive and vice versa