Converting python plugin-in shellout.py from gimp 2.x to 3.x

[denzjos]

After erasing the previous gimp 3.x files (including cleaning register), I reinstalled gimp 3.0.2-1. The following plugins have I installed (see picture), I still can't see the nikplugin, the other plugins are visible also the test-dialog under Filters/development/Demos.