load midi error 'IndexError: list assignment index out of range'

[enricocupellini]

I get this error 'IndexError: list assignment index out of range'
When I try to load this midi file: http://bachcentral.com/chorales/06Christus.mid
I call this method
midi = musicaiz.loaders.Musa(
file=midi_path
)

midi_path is correct and refers to my local file.
can you figure out the problem? thanks