public void reserveBook(int idNumber, String userName) {
        int numberOfBooksChecked = 0;
        for (Book item : books) {
            numberOfBooksChecked++;
            if ( item.getIdNumber() == idNumber)
            {
                AddBookIdAndUserToReservedList(idNumber,userName);
                myView.thanksUser();
                break;
            }
            if(numberOfBooksChecked == books.size()) {
                myView.informOfAbsenceOfBook();
            }
        }
    }