Design a system for a book store that allows the owner to keep track of the store’s inventory and members. The store sells two types of products: books and CDs. The store offers two types memberships to customers: regular memberships and premium memberships. The regular membership is free, while the premium members pay a fee every month. For this reason, the store keeps track of payment method and whether the fee is paid on time for the premium members. The system should keep track of the members and how much money each has spent at the store. The system also keeps track of the inventory of each product. Inheritance: 1. Member is extended by premium members. 2. Product is sub-classes into books and CDs