How to use the gaphas.painter.BoundingBoxPainter function in gaphas

def set_drawing_style(self, sloppiness=0.0):
        """
        Set the drawing style for the diagram. 0.0 is straight,
        2.0 is very sloppy.  If the sloppiness is set to be anything
        greater than 0.0, the FreeHandPainter instances will be used
        for both the item painter and the box painter.  Otherwise, by
        default, the ItemPainter is used for the item and
        BoundingBoxPainter for the box.
        """
        assert self.view
        view = self.view

        if sloppiness:
            item_painter = FreeHandPainter(ItemPainter(), sloppiness=sloppiness)
            box_painter = FreeHandPainter(BoundingBoxPainter(), sloppiness=sloppiness)
        else:
            item_painter = ItemPainter()
            box_painter = BoundingBoxPainter()

        view.painter = (
            PainterChain()
            .append(item_painter)
            .append(HandlePainter())
            .append(FocusedItemPainter())
            .append(ToolPainter())
        )

        view.bounding_box_painter = box_painter

        view.queue_draw_refresh()

def update_painters(self, view):
        sloppiness = self.properties.get("diagram.sloppiness", 0)

        if sloppiness:
            view.painter = FreeHandPainter(ItemPainter(), sloppiness)
            view.bounding_box_painter = FreeHandPainter(
                BoundingBoxPainter(), sloppiness
            )
        else:
            view.painter = ItemPainter()

Set the drawing style for the diagram. 0.0 is straight,
        2.0 is very sloppy.  If the sloppiness is set to be anything
        greater than 0.0, the FreeHandPainter instances will be used
        for both the item painter and the box painter.  Otherwise, by
        default, the ItemPainter is used for the item and
        BoundingBoxPainter for the box.
        """
        assert self.view
        view = self.view

        if sloppiness:
            item_painter = FreeHandPainter(ItemPainter(), sloppiness=sloppiness)
            box_painter = FreeHandPainter(BoundingBoxPainter(), sloppiness=sloppiness)
        else:
            item_painter = ItemPainter()
            box_painter = BoundingBoxPainter()

        view.painter = (
            PainterChain()
            .append(item_painter)
            .append(HandlePainter())
            .append(FocusedItemPainter())
            .append(ToolPainter())
        )

        view.bounding_box_painter = box_painter

        view.queue_draw_refresh()

cr.set_line_width(self.view.get_zoom_factor() / 4.)
            cr.identity_matrix()
            m = Matrix(*view.get_matrix_i2v(item))

            cr.set_antialias(ANTIALIAS_NONE)
            cr.translate(*m.transform_point(cx, cy))
            cr.rectangle(-side_length / 2., -side_length / 2., side_length, side_length)
            cr.set_source_rgba(*get_col_rgba(self.fill_color))
            cr.fill_preserve()
            cr.set_source_rgba(*get_col_rgba(self.border_color))
            cr.set_line_width(1)
            cr.stroke()
            cr.restore()


class BoundingBoxPainter(gaphas.painter.BoundingBoxPainter):
    """
    This specific case of an ItemPainter is used to calculate the bounding
    boxes (in canvas coordinates) for the items.
    """

    draw_all = True

    def _draw_item(self, item, cairo, area=None):
        cairo = gaphas.painter.CairoBoundingBoxContext(cairo)
        super(gaphas.painter.BoundingBoxPainter, self)._draw_item(item, cairo)
        bounds = cairo.get_bounds()

        view = self.view
        if isinstance(item, (StateView, NameView)):
            i2v = view.get_matrix_i2v(item).transform_point
            for index, handle in enumerate(item.handles()):

def _draw_item(self, item, cairo, area=None):
        cairo = gaphas.painter.CairoBoundingBoxContext(cairo)
        super(gaphas.painter.BoundingBoxPainter, self)._draw_item(item, cairo)
        bounds = cairo.get_bounds()

        view = self.view
        if isinstance(item, (StateView, NameView)):
            i2v = view.get_matrix_i2v(item).transform_point
            for index, handle in enumerate(item.handles()):
                if index >= 4:
                    break
                side_length = get_side_length_of_resize_handle(view, item)
                cx, cy = i2v(*handle.pos)
                bounds += (cx - side_length / 2, cy - side_length / 2, side_length, side_length)
        elif isinstance(item, ConnectionView):
            i2v = view.get_matrix_i2v(item).transform_point
            for h in item.handles():
                cx, cy = i2v(*h.pos)
                bounds += (cx, cy, 1, 1)