question: What art director was employed by M1 's producer and employed by a production company
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.film_art_director .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x2 .
  ?x1 ns:film.producer.film|ns:film.production_company.films M1 .
  ?x2 a ns:film.production_company
  }