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Should examples also be updated in the docs?

I looked over the docs, and I don't think there are any examples of subclassing these non-linear fitters? We could choose to update the docs out of an abundance of caution (adding a unused **kwargs wont hurt)?

Also, I was just wondering (without any deep understanding) if it would be better to have a dictionary like fitter_state (or info or whatever) that would have a key fit_param_indices in it and if in the future one would like to pass extra stuff then the function signature won't change. If this is non-sense, please ignore my comment.

heh, we had that and undid it in #16982 😆

@Cadair could your rebase and make sure pre-commit is happy ?

I will say it again, why can I not have the fekking github UI rebase button?

Re: GitHub rebase button -- I actually think I saw it a couple of times but it is like a unicorn. I dunno what triggers its appearance.

Thanks for your patience!

it is like a unicorn

Could be a feature flag: only deployed to a sample of users at a time (and then reverted).