def METHOD_NAME(api_client, event, registration):
    registration.enrolment_start_time = localtime() - timedelta(days=2)
    registration.enrolment_end_time = localtime() - timedelta(days=1)
    registration.save()
    reservation_data = {"seats": 1, "registration": registration.id}
    response = reserve_seats(api_client, reservation_data)
    assert response.status_code == status.HTTP_409_CONFLICT
    assert response.data["detail"] == "Enrolment is already closed."