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

            }
    }