def notify_restaurant_owners_about_positive_booked_customer_task(customer_id):
    reservations = ReservationManager.retrieve_by_customer_id_in_future(
        customer_id)
    for reservation in reservations:
        restaurant = reservation.restaurant
        owner = restaurant.owner
        notification = Notification(owner.id, customer_id, restaurant.id,
                                    reservation.start_time)
        NotificationManager.create_notification(notification=notification)
    def __retrieve_by_customer_id_in_future(message):
        from gooutsafe.dao.reservation_manager import ReservationManager
        reservations = ReservationManager.retrieve_by_customer_id_in_future(
            message['customer_id'])
        reservations = [
            reservation.serialize() for reservation in reservations
        ]

        return reservations