code: def menu_item(self, sub_assistant, path):
          
          if not sub_assistant[0].icon_path:
              menu_item = self.create_menu_item(sub_assistant[0].fullname)
          else:
              menu_item = self.create_image_menu_item(
                  sub_assistant[0].fullname, sub_assistant[0].icon_path
              )
          if sub_assistant[0].description:
              menu_item.set_has_tooltip(True)
              menu_item.connect("query-tooltip",
                                self.parent.tooltip_queries,
                                self.get_formatted_description(sub_assistant[0].description),
              )
          menu_item.connect("select", self.parent.sub_menu_select, path)
          menu_item.connect("button-press-event", self.parent.sub_menu_pressed)
          menu_item.show()
          return menu_item
docs: The function creates a menu item
          and assigns signal like select and button-press-event for
          manipulation with menu_item. sub_assistant and path