Add support for multiple volume layers in annotations

[philippotto]

Description:

• If ambiguous, the layer name has to be provided when reading from a volume layer in an annotation.

This PR is only fully compatible with webKnossos once scalableminds/webknossos#6028 (comment) is merged, since that PR fixes a naming issue in annotation downloads.

Issues:

• fixes Adapt volume annotation to support multiple layers #490

Todos:

Make sure to delete unnecessary points or to check all before merging:

• Updated Changelog

[jstriebel]

Nice! Mostly LGTM, I left a few minor comments, but approving already 👍

[jstriebel]

🎉

[philippotto]

@jstriebel mypy had some troubles with the _get_name_or_id method which is why I had to inline it 🤷 by the way, I noticed that mypy cannot really do typechecking on properties which use @cachedproperty. I noticed this because after I removed _get_name_or_id, mypy didn't complain even though it was still used. The decorator is currently only used in the annotation class. I briefly tried a newer mypy version because I saw python/typing#985, but this didn't fix the issue. Just FYI..

[jstriebel]

@jstriebel mypy had some troubles with the _get_name_or_id method which is why I had to inline it 🤷

Weird error, but glad you found an easy fix 👍

by the way, I noticed that mypy cannot really do typechecking on properties which use @cachedproperty. I noticed this because after I removed _get_name_or_id, mypy didn't complain even though it was still used. The decorator is currently only used in the annotation class. I briefly tried a newer mypy version because I saw python/typing#985, but this didn't fix the issue. Just FYI..

Good point! I guess the main problem is, that boltons (from where we importcachedproperty) is not typed. There are some stubs available here:
https://github.com/wcooley/python-boltons-stubs/blob/master/boltons-stubs/cacheutils.pyi#L127-L130
Seems like this is not published to pypi, but we can add them (or at least the ones we need) to our repo: https://mypy.readthedocs.io/en/stable/stubs.html

[philippotto]

Good point! I guess the main problem is, that boltons (from where we importcachedproperty) is not typed. There are some stubs available here:
https://github.com/wcooley/python-boltons-stubs/blob/master/boltons-stubs/cacheutils.pyi#L127-L130
Seems like this is not published to pypi, but we can add them (or at least the ones we need) to our repo: https://mypy.readthedocs.io/en/stable/stubs.html

Ah, makes sense 👍 I added the cachedproperty stubs, since I consider them relatively important for the type coverage of the annotation module.

[philippotto]

Thanks for pushing this. Yesterday, I was unsure how to fix this (strictly speaking one would need to check that user_bounding_boxes is not None). Ideally, it would always default to an empty list. However, that's likely out-of-scope for this PR. So, let's tackle it at a different point.

[jstriebel]

I agree, cleaning things up a bit more in the skeleton class is definitely a good idea, but let's defer this.

[jstriebel]

(and the assertion would clutter the user-facing example to much in my opinion, so i went for the ignore)