Assume that you have to develop a computer system for a university library. The library contains books and each book may have several copies. Only members of the library may borrow books. The system checks whether the potential borrower is a member of the library, and whether there is a reservation on the book. If both check succeed the system records that the book is on loan. Otherwise it refuses the loan.

A library member may ask to extend the loan of the book. The system then checks whether there is a reservation on the book. If so$,$ the system refuses to extend the loan. Otherwise it records the extension of the loan.

$($a$)$ Draw a use case diagram that represents the activities of the members of the library.

$($b$)$ Draw a sequence diagram that shows scenario of the use case Borrow copy of book in which the user is permitted to borrow the book, and the system records that the book is on loan