def update_book_data(self, book_id, json_data):
        if 'book_id' in json_data.keys() and json_data['book_id'] != book_id:
            raise IndexError("Id mismatched.")

        row_changed = Book.set_by_id(book_id, json_data)
        return self.get_book(book_id)
 def mark_book_unavaliable(self, book_id):
     Book.set_by_id(book_id, {"is_available": False})