question: What editor of M4 , M5 , and M6 was a film producer that M1 , M2 , and M3 employed
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.producer .
  ?x0 ns:film.editor.film M4 .
  ?x0 ns:film.editor.film M5 .
  ?x0 ns:film.editor.film M6 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3
  }