AttributeError: "PercussionChord' obiect has no attribute 'pitch'

[noodle0701]

I try to run the example python notebook with the example you provided
!python3 tension_calculation.py - example/input/55269aebbc2e7784ca2d1d4472141889.mid

but run into the error above. But is seems to work when I tried using another midi file. I am not sure if there is an error in the code or if there is wrong with the versions of some of the packages?