public void renew(BorrowedBook book)
 {
     book.setDaysToKeep(book.getDaysToKeep() + RENEWAL);
 }
        public BorrowedBook borrow(string bookTitle)
        {
            BorrowedBook book = new BorrowedBook(bookTitle);

            return(book);
        }
 public void borrowBook()
 {
     book = borrow.borrow(bookTitle);
 }
 public void returnIt(BorrowedBook book)
 {
     book = null;
 }