static async delete(notificationID, userID) {
        let bean = await R.findOne("notification", " id = ? AND user_id = ? ", [
            notificationID,
            userID,
        ]);

        if (! bean) {
            throw new Error("notification not found");
        }

        await R.trash(bean);
    }
Delete a notification
@param {number} notificationID ID of notification to delete
@param {number} userID ID of user who created notification
@returns {Promise<void>}