Stops the instance

def cmd_stop(self, argv, help):
        """Stops the instance"""
        parser = argparse.ArgumentParser(
            prog="%s stop" % self.progname,
            description=help,
        )
        instances = self.get_instances(command='stop')
        parser.add_argument("instance", nargs=1,
                            metavar="instance",
                            help="Name of the instance from the config.",
                            choices=sorted(instances))
        args = parser.parse_args(argv)
        instance = instances[args.instance[0]]
        instance.stop()