question: Which British film producer edited M1 , M2 , and M3 and edited a film
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.producer .
  ?x0 ns:film.editor.film ?x1 .
  ?x0 ns:film.editor.film M1 .
  ?x0 ns:film.editor.film M2 .
  ?x0 ns:film.editor.film M3 .
  ?x0 ns:people.person.nationality ns:m.07ssc .
  ?x1 a ns:film.film
  }