public ReservationRequest(String title, String author, String isbn,
     Branch requestor, Guid id)
 {
     _Title = title;
     _Author = author;
     _ISBN = isbn;
     _Requester = requestor;
     _RequestID = id;
 }
 public ReservationResponse(ReservationRequest request, bool reserved,
     Branch provider)
 {
     _RequestID = request.RequestID;
     _Reserved = reserved;
     _Provider = provider;
 }