question: Which film was distributed by a person and distributed by M1 , M2 , and M3
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.film .
  ?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor ?x1 .
  ?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor M1 .
  ?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor M2 .
  ?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor M3 .
  ?x1 a ns:people.person
  }