question: Which actor of M2 and M3 was a film editor that M1 was edited by and starred
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.editor .
  ?x0 ns:film.actor.film/ns:film.performance.character M2 .
  ?x0 ns:film.actor.film/ns:film.performance.character M3 .
  ?x0 ns:film.actor.film/ns:film.performance.film M1 .
  ?x0 ns:film.editor.film M1
  }