question: Did a film editor employed by M1 and M2 edit M3 's prequel
query: SELECT count(*) WHERE {
  ?x0 a ns:film.editor .
  ?x0 ns:film.editor.film ?x1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
  ?x1 ns:film.film.sequel M3
  }