Plugin will not register in Blender 4.0.2

[mcarlssen]

ENV - Blender 4.0.2, Windows 10 22H2.

ISSUE
With the current latest stable version of Blender, importing the plugin produces no result and it cannot be activated as normal.

TO REPRODUCE
Download plugin and attempt to import into Blender 4.0 per instructions in plugin README.
Blender console shows the following:
Modules Installed () from 'C:\\<...>' into '%APPDATA%<...>'
The plugin does not appear at the end of the Add > Curves menu.

EXPECTED RESULT
After importing plugin, Blender console should read:
Modules Installed (celtic-knot) from 'C:\\<...>' into '%APPDATA%<...>'

[mcarlssen]

Lovely plugin BTW - super cool math!

I did some cursory digging and found a relatively recent commit on an official add-on which seemed to indicate that the bl_options parameter could cause issues; to wit: "This previously did nothing (although the menus should not have defined them), since menus now have a bl_options so an invalid value caused an error."

Out of curiosity and blatant ignorance, I removed lines 780 and 948 (containing bl_options = {'REGISTER', 'UNDO'}) and attempted to re-import the plugin. This succeeded, immediately showing the plugin available for activation and a success console message.

I was unable to confirm through brief further research whether this is the correct solution - there seem to be other main-branch plugins in the official Blender repo which use this option, so somehow it's clearly not a breaking issue. However, I did discover that executing an UNDO immediately after running the script now crashes Blender entirely. So it might not be wrong, but it's not right.

[BorisTheBrave]

It's working fine for me. Did you forget to enable the plugin after installing it?