def METHOD_NAME(self, nameservers):
    db = Db()
    runner = CliRunner()
    obj = {'db': db.cfgdb}
    for ip in nameservers:
        # config dns nameserver add <ip>
        result = runner.invoke(self.config_dns_ns_add, [ip], obj=obj)
        print(result.exit_code, result.output)
        assert result.exit_code == 0
        assert ip in db.cfgdb.get_table('DNS_NAMESERVER')
        # Execute command once more
        result = runner.invoke(self.config_dns_ns_add, [ip], obj=obj)
        print(result.exit_code, result.output)
        assert result.exit_code != 0
        assert "nameserver is already configured" in result.output
        # config dns nameserver del <ip>
        result = runner.invoke(self.config_dns_ns_del, [ip], obj=obj)
        print(result.exit_code, result.output)
        assert result.exit_code == 0