Hey there,

I just wanted to use the new threading functionality together with multistart. This results in the following error:

raise InvalidMultistartError(optimagic.exceptions.InvalidMultistartError: Invalid batch evaluator: threading. Batch evaluator must be a Callable or one of 'joblib' or 'pathos'.

I think this can simply be fixed by adding threading to the list of batch_evaluators in multistart_options.py (line 250).

Originally posted by @nikithiel in #569 (comment)