Q3(a) 15 points] Consider a class MyListImplementation that keeps a doubly linked list with header and trailer sentinel nodes (referenced by instance variables of the list implementation called header and trailer). Assume that the Node class has the usual getter and setter methods. Write the sequence of Java statements that would be used within MyListImplementation, in order to insert the Node n at the front of the list. [You can use assignments to instance variables and you can call methods of the Node class, but do not call methods of the List ADT itself.] Q3(b) [5 points] A Comparator object is used in data structures, to allow the user to control the order placed on different objects by the structure. Give instructions that teach someone how to define a Comparator. In particular, you need to indicate any methods that the Comparator must have