question: Did a film that M2 and M3 edited star M1
query: SELECT count(*) WHERE {
  ?x0 a ns:film.film .
  ?x0 ns:film.film.edited_by M2 .
  ?x0 ns:film.film.edited_by M3 .
  ?x0 ns:film.film.starring/ns:film.performance.actor M1
  }