Type hints for `mne.preprocessing.ICA()` are narrower than their runtime behavior and documented usage.

Description of the problem

The runtime behavior and documentation allow a wider range of inputs than the current type annotations.

This causes false positives in static type checkers. Updating the type hints would align them with existing runtime behavior and documentation only, without modifying any runtime logic.

Steps to reproduce

from mne.preprocessing import ICA

ica = ICA(n_components=3, max_iter=1000)

Link to data

No response

Expected results

No type checker error, since the documentation specifies that max_iter accepts int | 'auto'.

Actual results

Static type checker reports:

Argument of type Literal[1000] cannot be assigned to parameter max_iter of type str

Additional information

This issue affects type checking only. Runtime behavior is correct.

I’d be happy to work on a fix for this if it’s confirmed as a bug.

Start by locating the mne.preprocessing.ICA() signature and its type annotation for max_iter, then compare it with the documented accepted values and the runtime behavior described here. Update only the annotation so the provided ICA(n_components=3, max_iter=1000) example passes static type checking without changing runtime logic.