public ActionResult AddBook(Book newBook, int?authorID)
 {
     try
     {
         bool isAuthorized = Administrator.IsAuthorized((string)(Session["UserSession"]), (int)(Session["UserRank"]), (int)Authorization.Rank.administrator);
         if (isAuthorized)
         {
             if (!BookManager.DoesIsbnExist(newBook.ISBN))
             {
                 if (ModelState.IsValid)
                 {
                     BookManager.AddABook(newBook, authorID);
                     return(RedirectToAction("ListBooks", "Book"));
                 }
             }
             else
             {
                 TempData["Error"] = "Something went wrong!";
                 return(RedirectToAction("AddBook"));
             }
         }
     }
     catch (Exception ex)
     {
         TempData["Error"] = "Something went wrong!";
         return(RedirectToAction("listBooks", "Book"));
     }
     TempData["Error"] = "Something went wrong!";
     return(RedirectToAction("AddBook"));
 }