Minor fix for Python 3.8 compatibility
Simple fix to something that doesn't work in 3.10 (which would break CI if it tried to run it)
list[AType] should be List[AType] (`List` from typing)
Simple fix to something that doesn't work in 3.10 (which would break CI if it tried to run it)
list[AType] should be List[AType] (`List` from typing)