/* We reviewed  BankAccountTester.java
   
  Also,
   -Look at Musian.java and Band.java and their Testers
   -A band has 3 members (musicians)
      This is an aggregation relation, i.e. an object (here a band) contains other object (here a musician)
     if b is a band, you can say   b.getMember1().getSalary()
       * b.getMember1() returns the first member of band b, the result is a musician
       * so the .getSalaray() part, is called on that musician and returns his/her salary.

   -In A1, an airport has 4 runways (again this is aggregation)
   
*/