An error occured in reviewer: unsupported operand type(s) for -=: 'int' and 'NoneType'

[deradox]

I'm pretty new to add-ons and programming, but I started getting this error recently. I disabled all of my add-ons and slowly added them back one-by-one. When I added Ankimon I got the error again. Is there a way to fix this?

Edit: I apologize, I completely missed someone else asking about this already. I believe the error was my main Pokemon (Meditite).