Update az_quiz_agent.py

[dunzel]

removed unused math import made prior argument optional as root Node is creating a MCTNode with prior=None added Type to usb_score child param

[foxik]

All nice ideas, thanks, merging, and updating your community-work score :+1:

[foxik]

BTW, I use math in my solution, but I forgot to mark it as a part not belonging to the template.