1. Write the scenario and draw a collaboration diagram for the action of returning a book to the library, as discussed in this section. 2. The PatronQueue class includes the method peek, which was not...

1. Write the scenario and draw a collaboration diagram for the action of returning a book to the library, as discussed in this section.

2. The PatronQueue class includes the method peek, which was not discussed earlier. This method expects no arguments and returns but does not remove the patron at the front of the queue. Does this method have preconditions? If so, what are they?