Real cash registers can handle both bills and coins. Design a single class that expresses the commonality of these concepts. Redesign the CashRegister class and provide a method for entering payments that are described by your class. Your primary challenge is to come up with a good name for this class.

Complete the following files:

CashRegister.java

CashRegisterTester.java

CashRegisterTester2.java

MonetaryUnit.java