question: What film editor directed M2 and M3 , wrote a film , and wrote M1
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.editor .
  ?x0 ns:film.director.film M2 .
  ?x0 ns:film.director.film M3 .
  ?x0 ns:film.writer.film ?x1 .
  ?x0 ns:film.writer.film M1 .
  ?x1 a ns:film.film
  }