Not seeing that error when I run this. Perhaps it's been fixed?
Nope. It's happening to me rn :(
It could be dependent on which specific version of Ren'Py is being used? I'm currently using Ren'Py 8.0.3 (Ren'Py 8, Python 3) from Sept 8/22. I've had code break because of versioning changes to Ren'Py before. Best of luck!