Write a class Savings Account that is similar to the Bank Account class, except that it has an added instance variable interest. Supply a constructor that sets both the initial balance and the interest rate. Supply a method add Interest (with no explicit parameter) that adds interest to the account. Write a Savings Account Tester class that con structs a savings account with an initial balance of $1,000 and an interest rate of 10 percent. Then apply the add Interest method and print the resulting balance. Also, com pute the expected result by hand and print it.