Zbrew is a streaming service similar to Hulu. A Zbrew customer account has a charge method that returns the monthly amount owed $($as a double$).$ A customer account also has a package with an abstract cost method that returns the cost of the package. $($The monthly charge is a fixed fee plus the cost of the package associated with the account.$)$ A package also has a quality: HD or SD$.$ There are five packages customers can choose from: Basic, Movies, Sports, News, and Combo. $($The cost algorithm may vary from package to package.$)$ As the name suggests, the Combo package allows customers to bundle together several packages, including combos of combos, etc. The Basic package is a legacy package left over from the early days when it was the only package available. Zbrew wants to reuse this package without modifying it$,$ but it doesn't extend Package. Zbrew also wants the ability to add new packages to the system without needing to modify the system. Draw a class diagram showing how you would design this part of Zebrew.