Question: One shortcoming of the drawer6 package is that a new state may be saved on the undo stack that is identical to the state immediately below it (e.g., if the user selects the same figures that are already selected or if the user drags a figure in a circle back to its starting place). Rewrite the package so that no new state is saved if the new state is equal to the previous state. To implement this feature, you will need to test the equality of two states, which, in turn, will require testing the equality of the drawings, and so the figures within the drawings. Therefore, equals methods will need to be added to many classes.