question: Which film producer employed M1 , employed M2 , M3 , M4 , and M5 , and employed M6 and M7
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.producer .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M1 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M2 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M3 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M4 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M5 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M6 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M7
  }