说明：  Digital Timer Write a program that simulates the digital timer, according to the specification discussed during the last week lecture. Implement the classes Timer and Display in the way as it is shown on slide 16 of the Unit 6. You program will consists three classes: Timer, Display and TestTimer. Timer will use Display class to create two objects: hours and minutes. TestTimer should create an object of class Timer and simulate work of the digital timer for 10 minutes.