def get_new_router_ids(self, context):
        existing_router_ids = self.initial['router_ids']
        add_router_ids = context['router_ids']
        return add_router_ids + existing_router_ids
dataset/ETHPy150Open openstack/horizon/openstack_dashboard/dashboards/project/firewalls/forms.py/AddRouterToFirewall.get_new_router_ids/original