Fix mypy issues uncovered by compiling with mypyc

[DanielNoord]

Taken from #2586

Some fixes unearthed by code compiled by mypyc being stricter about the actual types at runtime.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.39%. Comparing base (d75b093) to head (8790581).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2587   +/-   ##
=======================================
  Coverage   99.39%   99.39%           
=======================================
  Files          41       41           
  Lines        3146     3147    +1     
  Branches      680      680           
=======================================
+ Hits         3127     3128    +1     
  Misses         11       11           
  Partials        8        8           

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