You are asked to write a java discount system for a beauty salon, which provides services and sells beauty products. It offers $3$ types of memberships: Premium, Gold and Silver. Premium, Gold, and Silver members receive a discount of $20\%,15\%,$ and $10\%,$ respectively, for all services provided. Customers without membership receive no discount. All members receive a flat $10\%$ discount on products purchased $($this might change in future$).$ Your system shall consist of three classes: Customer, DiscountRate and Visit, as shown in the class diagram. It shall compute the total bill if a customer purchase $x of products and $y of services, for a visit. The class DiscountRate contains only static variables and methods $($underlined in the class diagram$).$