question: What film director did M1 and M2 employ , M3 , M4 , and M5 employ , and M6 and M7 employ
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.director .
  ?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 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M4 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M5 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M6 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M7
  }