question: Was M1 employed by M2 , employed by M3 , employed by a producer of M0 , and employed by M4
query: SELECT count(*) WHERE {
  ?x0 ns:film.producer.film|ns:film.production_company.films M0 .
  M1 ns:people.person.employment_history/ns:business.employment_tenure.company ?x0 .
  M1 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
  M1 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
  M1 ns:people.person.employment_history/ns:business.employment_tenure.company M4
  }