question: Was a film producer that employed M1 and employed M2 M3 's employer
query: SELECT count(*) 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
  }