Database: music_2
Question: What instrument did the musician with last name "Heilo" use in the song "Le Pop"?
SQL:
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"