question: Was a film 's Mexican editor M1 's producer
query: SELECT count(*) WHERE {
  ?x0 ns:film.editor.film ?x1 .
  ?x0 ns:film.producer.film|ns:film.production_company.films M1 .
  ?x0 ns:people.person.nationality ns:m.0b90_r .
  ?x1 a ns:film.film
  }