def METHOD_NAME(book_id):
    is_present = ub.session.query(ub.KoboSyncedBooks).filter(ub.KoboSyncedBooks.book_id == book_id)\
        .filter(ub.KoboSyncedBooks.user_id == current_user.id).count()
    if not is_present:
        synced_book = ub.KoboSyncedBooks()
        synced_book.user_id = current_user.id
        synced_book.book_id = book_id
        ub.session.add(synced_book)
        ub.session_commit()