question: Who was a film director that M1 and M2 were directed by and were edited by
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:people.person .
  ?x0 ns:film.director.film M1 .
  ?x0 ns:film.director.film M2 .
  ?x0 ns:film.editor.film M1 .
  ?x0 ns:film.editor.film M2
  }