Plugin won't show in menu - Printable Version

Code:
#!/usr/bin/env python3

# GIMP plugin to add a new desaturated layer



import sys



import gi

gi.require_version('Gimp', '3.0')

from gi.repository import Gimp

gi.require_version('GimpUi', '3.0')

from gi.repository import GimpUi

from gi.repository import GLib



def add_desaturate_layer(procedure, run_mode, image, drawables, config, data): ### Separate function not a method of the plugin

    # Duplicate the current layer

    source_layer=drawables[0] ### Drawables is a list (with a single element here)

    new_layer = source_layer.copy()

    new_layer.set_name("Desaturate")

    image.insert_layer(new_layer,

                       source_layer.get_parent(),

                       image.get_item_position(source_layer)) ### technically, you should insert in the layers's parent, above the source layer



    # Apply the desaturation

    new_layer.desaturate(Gimp.DesaturateMode.LIGHTNESS)  ### desaturate is method of Gimp.Drawable



    return procedure.new_return_values(Gimp.PDBStatusType.SUCCESS, GLib.Error()) ### Procedure has to return something



class AddDesaturateLayerPlugin(Gimp.PlugIn):



    def do_query_procedures(self):

        return ['python-fu-add-desaturate-layer']



    def do_activate(self):

        pass



    def do_create_procedure(self, name):

        if name == 'python-fu-add-desaturate-layer':

            print(f'------------- Creating {name}')

            procedure = Gimp.ImageProcedure.new(    ### Gimp.ImageProcedure, not just plain Gimp.Procedure

                self, name, Gimp.PDBProcType.PLUGIN, add_desaturate_layer, None)

            procedure.set_sensitivity_mask (Gimp.ProcedureSensitivityMask.DRAWABLE) ### Only enable if there is exactly one selected drawable

            procedure.set_menu_label("Add Desaturate Layer")

            procedure.add_menu_path('<Image>/Filters/')

            procedure.set_attribution("YourName", "YourContact", "Adds a desaturated layer")

            procedure.set_documentation(

                "Adds a new desaturated layer to the active image.",

                "Adds a new desaturated layer to the active image.",

                name,

            )

            return procedure



Gimp.main(AddDesaturateLayerPlugin.__gtype__,sys.argv) ### 2nd arg normally the sys.argv