Golden Challenge, Adding BNRContainer class. The following is the problem as described in the book:

Create a subclass of BNRItem named BNRContainer. An instance of BNRContainer should have an array of subitems that contains instances of BNRItem. Printing the description of a BNRContainer object should show you the name of the container, its value in dollars (a sum of all items in the container plus the value of the container itself), and a list of every instance of BNRItem it contains. A properly-written BNRContainer class can contain instances of BNRContainer. It can also report back its full value and every contained item properly.