From the current signature it appears as `fallback` argument is not optional. Changed it to have a default `None` value, similar to `angle(other, fallback=None)`. Noticed this issue working with fake-bpy-module that generates typing based on Blender docs - https://github.com/nutti/fake-bpy-module/issues/326. Pull Request: https://projects.blender.org/blender/blender/pulls/132052