Cannot draw any element

[alberdibenat]

Extension installed successfully, every option is shown in Inkscape. However, once I try to draw any element I get this error message:

Traceback (most recent call last):
File "/home/qou/.config/inkscape/extensions/inkscape-raytracing/inkscape_raytracing/lens.py", line 224, in
Lens().run()
File "/usr/share/inkscape/extensions/inkex/base.py", line 131, in run
self.save_raw(self.effect())
File "/usr/share/inkscape/extensions/inkex/extensions.py", line 193, in effect
for child in fragment:
File "/home/qou/.config/inkscape/extensions/inkscape-raytracing/inkscape_raytracing/lens.py", line 41, in generate
d = self.svg.viewport_to_unit(f"{opts.diameter}{opts.diameter_unit}")
File "/usr/share/inkscape/extensions/inkex/elements/_base.py", line 165, in getattr
raise AttributeError(f"Can't find attribute {self.typename}.{name}")
AttributeError: Can't find attribute SvgDocumentElement.viewport_to_unit