Changes for Listing 2.11
Changed for Listing 2.12
Changed for Listing 2.13
Changed for Listing 2.14
Changed for Listing 2.15
Fixed spelling error.
Changes for Listing 2.16.
Changed typo from Listing 2.13 that was not allowing the spec to run properly.  Was receiving and undefined method for expired with an exclamation point
Changes for listing 2.17
Changes for listing 2.17