Initial PR for a new structure of exceptions.

[KochC]

Summary

Initial PR for a new structure of exceptions.

Checklist

• You agree with our CLA
• Included tests (or is not applicable).
• Updated documentation (or is not applicable).
• Used pre-commit hooks to format and lint the code.
• Upgrade plan implemented / downwards compatibility implemented

[jonas-w]

Extensions? You mean exceptions?

[KochC]

Extensions? You mean exceptions?

yes, sorry for the confusion 😉 Before merging I suggest to discuss if the new structure makes sense, and then continue with some more examples before a final merge.

[jonas-w]

Extensions? You mean exceptions?

yes, sorry for the confusion wink Before merging I suggest to discuss if the new structure makes sense, and then continue with some more examples before a final merge.

No problem ^^. Could you please fix the merge conflict, that the tests can run?

[jonas-w]

LGTM, but ffs should be renamed to something more descriptive.

[nicornk]

Thanks for the contribution @KochC . I need to review this properly - please keep it open for now.

[jonas-w]

We will also need deprecation warnings, otherwise it may instantly break code other people wrote.

[nilskch]

At the end before merging into the main branch, I suggest to squash the commits into one and reference the issue you raised in the commit message by adding "(#5)" at the end of the commit message.