def get_redshift_iam_role_arn(iam, iam_role_name):
    """
    Retrieves IAM Role ARN

    Args:
        iam: IAM client.
        iam_role_name: IAM Role name.

    Returns:
        IAM ROLE ARN

    """
    return iam.get_role(RoleName=iam_role_name)['Role']['Arn']