On appeal, defendant contends that his plea of guilty, entered on June 2, 1978, to the charges of simple robbery, La.R.S. 14:65, and attempted first degree murder, La.R.S. 14:27 (14:30), was not understanding and voluntary. Such a contention is not properly raised on appeal, but must be pressed by an application for a writ of habeas corpus in the district court. See State ex rel. Clark v. Marullo, 352 So.2d 223 (La. 1977); State v. Crosby, 338 So.2d 584 (La. 1976).

Accordingly, defendant’s conviction and sentence are affirmed.