Consider the credit card example  posted here and extended in the following three ways:

1. Challenge #1: Support a platinum card that provides twice the points for airline travel purchases and give john a platinum card. Note all transactions whose descriptions have "air" in them are recognized as airline purchases.
    
2. Challenge #2: Create an appropriate exception for when the number of transactions exceeds the Transaction Limit. Catch this exception in Driver and if the exception occurs, write a suitable message to System.err.
    
3. Challenge #3: Provide an implementation of equals on CardHolder so that the cardholders mary and mary2 match.