Thanks to all. I ended up using Sequence for the list part and Mapping for the dict part, which does require "import typing" which I would rather have avoided.
Karsten -- GPG 40BE 5B0E C98E 1713 AFA6 5BC0 3BEA AC80 7D4F C89B -- https://mail.python.org/mailman/listinfo/python-list
