question: Was M2 written by M1 's writer , written by a person , executive produced by M3 , and written by M4
query: SELECT count(*) WHERE {
  ?x0 a ns:people.person .
  ?x1 ns:film.writer.film M1 .
  M2 ns:film.film.executive_produced_by M3 .
  M2 ns:film.film.written_by ?x0 .
  M2 ns:film.film.written_by ?x1 .
  M2 ns:film.film.written_by M4
  }