Define a public class named Flip with a single public instance method named flop that takes no parameters and returns a Boolean. Flip should also provide a single public constructor that accepts a Boolean argument and sets the initial state of the Flip instance.

Flip maintains one piece of private state: the Boolean. Calling flop changes the Boolean from true to false or false to true and returns the new (not the old) state of the Boolean. So, for example:

Note that the internal state should be private.