question: Who was M1 's Mexican Spanish writer
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:people.person .
  ?x0 ns:film.writer.film M1 .
  ?x0 ns:people.person.nationality ns:m.06mkj .
  ?x0 ns:people.person.nationality ns:m.0b90_r
  }