Decorator to ensure that the named container exists.

def _ensure_exists(wrapped):
    '''
    Decorator to ensure that the named container exists.
    '''
    @functools.wraps(wrapped)
    def check_exists(name, *args, **kwargs):
        if not exists(name):
            raise CommandExecutionError(
                'Container \'{0}\' does not exist'.format(name)
            )
        return wrapped(name, *args, **salt.utils.args.clean_kwargs(**kwargs))
    return check_exists