What instrument did the musician with last name "Heilo" use in the song "Le Pop"?
select t4.instrument from performance as t1 join band as t2 on t1.bandmate = t2.id join songs as t3 on t3.songid = t1.songid join instruments as t4 on t4.songid = t3.songid and t4.bandmateid = t2.id where t2.lastname = "Heilo" and t3.title = "Le Pop"