krita-plugins/page_slicer_docker/__init__.py

from krita import DockWidgetFactory, DockWidgetFactoryBase
from .page_slicer_docker import PageSlicer

DOCKER_ID = 'page_slicer'
instance = Krita.instance()
dock_widget_factory = DockWidgetFactory(DOCKER_ID,
                                        DockWidgetFactoryBase.DockRight,
                                        PageSlicer)

instance.addDockWidgetFactory(dock_widget_factory)