Fixing N-dimensional histogram entry ordering

[yimuchen]

• Fixing histogram order.
  • Adding example to example notebook for user inspection
• Fixing python styling issues according to flake8

---

📚 Documentation preview 📚: https://hepdata-lib--248.org.readthedocs.build/en/248/

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (3ed9148) 87.71% compared to head (2bcc68b) 87.70%.

Files	Patch %	Lines
hepdata_lib/hist_utils.py	80.00%	0 Missing and 1 partial ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #248      +/-   ##
==========================================
- Coverage   87.71%   87.70%   -0.02%     
==========================================
  Files           5        5              
  Lines        1083     1082       -1     
  Branches      231      231              
==========================================
- Hits          950      949       -1     
  Misses         93       93              
  Partials       40       40              

Flag	Coverage Δ
unittests-3.10	87.70% <80.00%> (-0.02%)	⬇️
unittests-3.6	87.39% <80.00%> (-0.02%)	⬇️
unittests-3.7	87.39% <80.00%> (-0.02%)	⬇️
unittests-3.8	87.52% <80.00%> (-0.02%)	⬇️
unittests-3.9	87.52% <80.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[clelange]

Thanks, looks good to me.