4. (40) The class defined below, MyLiat, is a recursive implementation of the List of all the remain- usunl Python 1ist class. The instance variables representing a MyLint objed are firat, an int valtue at position 0, and rest, a My ing valaes in the list. The interface is restricted to have only three methods init., append, and pop, which only removes the last item. As restrictive as this appears, it suffices to play the role of a structure much used in computer science called a Stack. Read the code, and answer the questions which follow: class MyList Cobject): def init.(self) self..first -None self. rest-None def append (aelf, item): if self.first None: self. .firet -item self. .rest MyListO else self. .rest.append (self, first) self..first item def pop(self): if self-fir t ". None : return None else i tem self..first self. .firt self. .rest.pop return item a. Identify, by circling and labeling, which parts of the method defi- nitions for append and pop are base case and recursive case. b. Draw a class symbol diagram for MyList, giving all instance vari- ables and methods. For each instance variable, specify its type. c. Explain how this class definition is both structurally and function d. Using box-and-arrow diagrams, show the state of Python memo (Assume all items appended and popped are integers.) ally recursive. after each of the following four statements are executed: 1st = MyList() 1st.append (7) 1st.append (11) n 1st.pop ()