question: Who was a Chinese film producer that M2 was written by and M3 was written by
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.producer .
  ?x0 a ns:people.person .
  ?x0 ns:film.writer.film M2 .
  ?x0 ns:film.writer.film M3 .
  ?x0 ns:people.person.nationality ns:m.0d05w3
  }