public void addBook(Book newAddbook) {
        Book bookCopy = null;
        for (Book book : bookMap.values()) {
            if (book.equals(newAddbook)) {
                book.addCopy();
                bookCopy = book;
                return;
            }
        }
        if (bookCopy == null) {
            Integer id = uniqueID++;
            newAddbook.setId(id);;
            bookMap.put(id, newAddbook);
        }
    }