How to use the napari.layers.image._constants.Rendering function in napari

def _on_iso_threshold_change(self):
        rendering = self.layer.rendering
        if isinstance(rendering, str):
            rendering = Rendering(rendering)
        if self.layer.dims.ndisplay == 3 and rendering == Rendering.ISO:
            self.node.threshold = float(self.layer.iso_threshold)
            self.node.shared_program['u_threshold'] = self.node.threshold

def rendering(self, rendering):
        if isinstance(rendering, str):
            rendering = Rendering(rendering)

        self._rendering = rendering
        self.events.rendering()

def _toggle_iso_threhold_visbility(self):
        rendering = self.layer.rendering
        if isinstance(rendering, str):
            rendering = Rendering(rendering)
        if rendering == Rendering.ISO:
            self.isoThesholdSilder.show()
            self.isoThesholdLabel.show()
        else:
            self.isoThesholdSilder.hide()
            self.isoThesholdLabel.hide()

def _toggle_iso_threhold_visbility(self):
        rendering = self.layer.rendering
        if isinstance(rendering, str):
            rendering = Rendering(rendering)
        if rendering == Rendering.ISO:
            self.isoThesholdSilder.show()
            self.isoThesholdLabel.show()
        else:
            self.isoThesholdSilder.hide()
            self.isoThesholdLabel.hide()