Refactoring

[RemDelaporteMathurin]

Proposed changes

Describe the big picture of your changes here to communicate to the maintainers why we should accept this pull request. If it fixes a bug or resolves a feature request, be sure to link to that issue.

Types of changes

What types of changes does your code introduce to FESTIM?

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code refactoring
• Documentation Update (if none of the other choices apply)
• New tests

Checklist

• Black formatted
• Unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

[codecov]

Codecov Report

Attention: Patch coverage is 91.09589% with 13 lines in your changes missing coverage. Please review.

Project coverage is 96.00%. Comparing base (d061987) to head (64a59c2).
Report is 28 commits behind head on fenicsx.

Files with missing lines	Patch %	Lines
src/festim/hydrogen_transport_problem.py	89.25%	13 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           fenicsx     #963      +/-   ##
===========================================
- Coverage    96.14%   96.00%   -0.15%     
===========================================
  Files           46       45       -1     
  Lines         2567     2600      +33     
===========================================
+ Hits          2468     2496      +28     
- Misses          99      104       +5     

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