Fix a couple of pyupgrade issues

[mikemanger]

pyupgrade highlighted a couple of minor changes:

• Use python 3 super function calls
• Use f strings in a couple of places

I can add a pre-commit config if wanted?

[sklarsa]

I can add a pre-commit config if wanted?

I don't think we need to do it as long as we enforce new language features in reviews going forward.

[sklarsa]

Thank you again for the housekeeping work