[LAU] Merry Christmas Python Chiptune (sortof)

[Ivan K]

When I execute:
> python pybells_2017.py

I get the following message:

> Calculating notes...
> Traceback (most recent call last):
>   File "pybells_2017.py", line 203, in <module>
>     0, MAX_AMPLITUDE, NOTE_DURATION * ATTACK_FACTOR, MASTER_VOLUME
>   File "pybells_2017.py", line 60, in make_ramp
>     for _ in range(1, size):
> TypeError: range() integer end argument expected, got float.

and no .wav file is created.  How do I fix this?
Am I missing a python library ?

Thank you.