question: What German film producer played M2 and played M3
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.producer .
  ?x0 ns:film.actor.film/ns:film.performance.character M2 .
  ?x0 ns:film.actor.film/ns:film.performance.character M3 .
  ?x0 ns:people.person.nationality ns:m.0345h
  }