⚡ Speedup ModelPrivateAttr

[lig]

Change Summary

This should speedup using private model attributes as using hasattr is significantly faster than getattr in case of an attribute doesn't not exist. It seems likely that ModelPrivateAttr would be used without a custom __set_name__ more often.

>>> import timeit
>>> timeit.timeit("hasattr(a, 'foo')", setup="a = type('A', (), {})")
0.17332394601544365
>>> timeit.timeit("try: getattr(a, 'foo')\nexcept AttributeError: pass", setup="a = type('A', (), {})")
0.38944376300787553

Related issue number

None

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• changes/<pull request or issue id>-<github username>.md file added describing change
  (see changes/README.md for details)
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

Selected Reviewer: @dmontagu

[lig]

please review

[dmontagu]

LGTM