question: Were M2 and M3 executive produced by a British film editor
query: SELECT count(*) WHERE {
  ?x0 a ns:film.editor .
  ?x0 ns:people.person.nationality ns:m.07ssc .
  M2 ns:film.film.executive_produced_by ?x0 .
  M3 ns:film.film.executive_produced_by ?x0
  }