Inline single-use variables, update .py files formatting

[KJhellico]

Proposed change

Remove once-used variables, update .py files formatting.

Type of change

• New country/market holidays support (thank you!)
• Supported country/market holidays update (calendar discrepancy fix, localization)
• Existing code/documentation/test/process quality improvement (best practice, cleanup, refactoring, optimization)
• Dependency update (version deprecation/pin/upgrade)
• Bugfix (non-breaking change which fixes an issue)
• Breaking change (a code change causing existing functionality to break)
• New feature (new holidays functionality in general)

Checklist

• I've followed the contributing guidelines
• I've successfully run make check, all checks and tests are green

[sonarqubecloud]

Quality Gate failed

Failed conditions
3.5% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (5f37ecc) to head (553fd6b).
Report is 1 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff            @@
##               dev     #2161   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          194       194           
  Lines        11559     11540   -19     
  Branches      1641      1641           
=========================================
- Hits         11559     11540   -19     

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[arkid15r]

LGTM 👍

[PPsyrius]

LGTM 🌐