How do I get the spline length driven by modifiers Hooks?

I am finding myself scripting some kind of addon that shows for the first time the great advantage of the Spline IK. However, I find the python code as described here docs.blender.org/api/current/bpy.types.Spline.html not useful enough. It does as described but I would consider changing its name like calc_length() -> calc_rest_length() because it shows the rest position of the Spline.

I ask the blender developers to provide a function to actually calculate the spline length driven by the hooks modifiers.