Could not create instance of operator to call callback function error in Blender 4.4 add-ons

When running some add-ons in Blender 4.4, users began to encounter an error: Could not create instance of _OPERATOR_ to call callback function ‘_function_’. This is due to recent changes in the Blender Python API for Blender 4.4.

Getting the angle between edges using Blender Geometry Nodes if several edges come out of a vertex

In the “Calculating the angle between edges using Blender Geometry Nodes” post, I was asked what to do in a more general case, when several edges come out of one vertex of the mesh? This problem can also be solved using Geometry Nodes, but the approach to the solution here is slightly different.