public function authorize_cache_security_group_ingress($cache_security_group_name, $ec2_security_group_name, $ec2_security_group_owner_id, $opt = null)
    {
        if (!$opt) $opt = array();
        $opt['CacheSecurityGroupName'] = $cache_security_group_name;
        $opt['EC2SecurityGroupName'] = $ec2_security_group_name;