Define our own functions when methods does not match NLPModels

[blegat]

It probably cleaner and less confusing

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.36%. Comparing base (8111077) to head (f296665).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #53   +/-   ##
=======================================
  Coverage   99.36%   99.36%           
=======================================
  Files          23       23           
  Lines        1258     1258           
=======================================
  Hits         1250     1250           
  Misses          8        8           

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