def METHOD_NAME(self, *args):
    if self.disabled_msg:
        return
    # toggle visibility of markers
    for mark in self.marks.values():
        mark.visible = self.is_active
    # subscribe/unsubscribe to keypress events across all viewers
    for viewer in self.app._viewer_store.values():
        if not hasattr(viewer, 'figure'):
            # table viewer, etc
            continue
        callback = self._viewer_callback(viewer, self._on_viewer_key_event)
        if self.is_active:
            viewer.add_event_callback(callback, events=['keydown'])
        else:
            viewer.remove_event_callback(callback)