def _construct_arn(owner_id, region_name, instance_id):
    """
    Args:
        owner_id (str): owner id
        region_name (str) : region that EC2 is deployed
        instance_id (str) : instance on of the EC2

    Returns:
        EC2 arn
    """
    return 'arn:aws:ec2:{region}:{owner}:instance/instance-id/{instance_id}'.format(
        region=region_name,
        owner=owner_id,
        instance_id=instance_id,
    )