Book checkout scenario at a library: The Worker tells the System the identity of a patron who wishes to check out books. The System confirms that the patron is allowed to check out books and remembers the patron's identity. The Worker tells the system the identity of a book this patron is checking out. The System confirms that the book can circulate based on book type, calculates the due date based on whether the patron is a faculty member or a student, and records that the patron has checked out this book, which is due on the calculated due date, and makes that information available from the library catalog. The System tells the Worker the due date (which also confirms that the book has been checked out).

Identify two valid classes, one class generalization, and two valid associations from the problem scenario provided.