def cleanup(self):
        """
        Called when the application closes and the module widget is destroyed.
        """
        self._turninig = True
        self.clearScene(clearAllVolumes=True)
        self.removeObservers()
        self.resetPointList(
            self.ui.dgPositiveControlPointPlacementWidget,
            self.dgPositivePointListNode,
            self.dgPositivePointListNodeObservers, )
        self.dgPositivePointListNode = None
        self.resetPointList(
            self.ui.dgNegativeControlPointPlacementWidget,
            self.dgNegativePointListNode,
            self.dgNegativePointListNodeObservers, )
        self.dgNegativePointListNode = None

        Called when the application closes and the module widget is destroyed.
        
EISeg/med3d/EISegMed3D/EISegMed3D.py