Hey all,
I forked the package and updated what I could to make it 1.18+ compatible. If anyone wants to access it, here's the repo, and here's the PyPi link. You can install it with "pip install anvil-new", and for now the import is still "import anvil" (but I might change that). My fork does only support versions 1.16 and above AFAIK.
All credit to matcool, and if there's anything I forgot to do to give them credit let me know.