A few changes have been made to Twitch since that example was posted.
GITHUB user derekmhh has posted an updated version that should work, but the updates haven’t been merged into the main branch. The new version of the example bot can be found here: https://github.com/derekmhh/twitch-IRC-bots/blob/233eb0db52c3072c9a8fcdea09537aee647d5ae5/python/chatbot.py