'Returns appliance asn.'

def get_asn(self):

    svc = '/api/system/v1/version'
    ret = self.rclient.get(svc)
    if (ret.status != restclient.Status.OK):
        exception_msg = (_('Error    getting    appliance    version    details.    Return    code:    %(ret.status)d    Message:    %(ret.data)s    .') % {'ret.status': ret.status, 'ret.data': ret.data})
        LOG.error(exception_msg)
        raise exception.VolumeBackendAPIException(data=exception_msg)
    val = json.loads(ret.data)
    return val['version']['asn']
