Raise exception in add_year

[gidden]

Required: write a single sentence that describes the changes made by this PR.

This PR raises an exception at the start of add_year()

How to review

Required: describe specific things that reviewer(s) must do, in order to ensure that the PR achieves its goal.
If no review is required, write “No review:” and describe why.

Confirm that tests still pass and advise on any issues that arise as a result of non-passage

PR checklist

• Continuous integration checks all ✅

• Add or expand tests; coverage checks both ✅
• Add, expand, or update documentation.
• Update release notes.

[gidden]

Please advise on whether to run black here which results in a large diff

[LauWien]

Please advise on whether to run black here which results in a large diff

Hm, possible we can create a new PR where we run black in the whole repository and then rebase this PR once merged? @khaeru what do you think?

[LauWien]

Please advise on whether to run black here which results in a large diff

I just see your branch is out of date with master, I guess a rebase will do the trick.

[gidden]

ah hah - let me rebase and cherry-pick

[glatterf42]

Closing this since always raising this exception does not seem the correct way forward to me. And if we do decide to take that route later on, we can always revisit this PR and copy the lines from here.