This kind of methods should use classes instead of instances. Use [this method](https://github.com/logoff/opennaas/blob/f2fdemo/L3VLAN/extensions/bundles/router.model/src/main/java/org/opennaas/extensions/router/model/System.java#L130) and [this call to the method](https://github.com/logoff/opennaas/blob/f2fdemo/L3VLAN/extensions/bundles/router.actionsets.junos/src/main/java/org/opennaas/extensions/router/junos/commandsets/digester/VLANParser.java#L198) as guideline to mimic.