Serving local meshes via Python

Hi!

I would like to serve meshes from a local source (e.g. a folder with .obj files) - similar to your [example_skeletons.py](https://github.com/google/neuroglancer/blob/master/python/examples/example_skeletons.py) example but for meshes. I was thinking I could subclass `LocalVolume` and replace the [`get_object_mesh`](https://github.com/google/neuroglancer/blob/b5b19f4e3a5c4795ad410e13ffe5b04444024c02/python/neuroglancer/local_volume.py#L193) method. Would that be a viable solution? If so, what's the expected return value of `get_object_mesh`?

Many thanks,
Philipp