def METHOD_NAME(self):
    """Add actions to zoom the viewer"""
    m = self._menu
    m.addSeparator()
    sm = QMenu(m)
    sm.setTitle(_("Zoom"))
    m.addMenu(sm)
    ac = self._actionCollection
    sm.addAction(ac.viewer_fit_width)
    sm.addAction(ac.viewer_fit_height)
    sm.addAction(ac.viewer_fit_both)
    sm.addSeparator()
    sm.addAction(ac.viewer_zoom_in)
    sm.addAction(ac.viewer_zoom_out)
    sm.addAction(ac.viewer_zoom_original)