Remove unneeded abstractions in model code (2)

[damonbayer]

Redo of #187, which ended up with a mangled git history that I couldn't resolve.

Cleaning up this model in preparation for #202.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.39%. Comparing base (71228e5) to head (a2beff5).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #207      +/-   ##
==========================================
- Coverage   92.51%   92.39%   -0.12%     
==========================================
  Files          40       40              
  Lines         895      881      -14     
==========================================
- Hits          828      814      -14     
  Misses         67       67              

Flag	Coverage Δ
unittests	92.39% <100.00%> (-0.12%)	⬇️

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[AFg6K7h4fhy2]

Variable clarification and removal of sample() wrappers are appropriate and useful. Thank you. Hanging colon conversation addressed; due to pre-commit hooks, either black or ruff.