Problem: The government now requires that DNSs should now maintain a secret blacklist of IPAs that must not be returned, even if the domain name exists. Without changing your DNS class from problem 1,

define a new class that extends your old class, adding:

a method for adding an IPA to the secret blacklist; and

a private attribute for the blacklist.

Hint: it may be called a blacklist, but is a Python list the most efficient data structure to use here? 2 You must also override the lookup method so that it returns None for blacklisted IPA, even if they do exist. Write a test program that allows the user to test the new class.