def tearDown(self):
        super(SimpleInstanceTest, self).tearDown()
        CONF.network_label_regex = self.orig_conf
        CONF.ip_start = None
def get_primary_domain(self):
        """
        Returns the primary domain of the tenant
        """
        try:
            domain = self.domains.get(is_primary=True)
            return domain
        except get_tenant_domain_model().DoesNotExist:
            return None