What was a film that was written by M1 and M2 and was directed by M3 and M4
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.film .
?x0 ns:film.film.directed_by M3 .
?x0 ns:film.film.directed_by M4 .
?x0 ns:film.film.written_by M1 .
?x0 ns:film.film.written_by M2
}