Fix Matrix Testing & Typing Error

[freemansw1]

Resolves #467 . Note that the initial commit should fail CI as I haven't implemented the typing fix yet (intentionally).

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.75%. Comparing base (706b3ee) to head (e527b5e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #468      +/-   ##
==========================================
+ Coverage   60.67%   60.75%   +0.07%     
==========================================
  Files          23       23              
  Lines        3537     3544       +7     
==========================================
+ Hits         2146     2153       +7     
  Misses       1391     1391              

Flag	Coverage Δ
unittests	60.75% <100.00%> (+0.07%)	⬆️

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[w-k-jones]

Great, thanks for fixing this! Happy for this to be merged directly into main as soon as the remaining tests have passed, and released as 1.5.5

[JuliaKukulies]

Thanks @freemansw1 ! I am also happy for you to merge this as soon as you see this.

Just a quick question: would it make sense to import annotations in all test files and submodules, even those that currently do not contain characters that are affected?