Returns query set of all plugins belonging to plugin point.

        Example::

            for plugin_instance in MyPluginPoint.get_plugins_qs():
                print(plugin_instance.get_plugin().name)

def get_plugins_qs(cls):
        """
        Returns query set of all plugins belonging to plugin point.

        Example::

            for plugin_instance in MyPluginPoint.get_plugins_qs():
                print(plugin_instance.get_plugin().name)

        """
        if is_plugin_point(cls):
            point_pythonpath = cls.get_pythonpath()
            return Plugin.objects.filter(point__pythonpath=point_pythonpath,
                                         status=ENABLED).\
                order_by('index')
        else:
            raise Exception(_('This method is only available to plugin point '
                              'classes.'))