Doesn't work anymore

[antaljani]

As I followed the instructions, I got this runtime error:
main.py output:
Traceback (most recent call last):
File "main.py", line 7, in
File "kb.py", line 30, in init
File "kmk/scanners/keypad.py", line 52, in init
TypeError: 'value_when_pressed' argument required

I have no idea, what is the problem, but apparently not workig.