(725 ILCS 5/113-4.1) (from Ch. 38, par. 113-4.1)
    Sec. 113-4.1. Plea of nolo contendere.
    A defendant who is charged with a violation of the Illinois Income Tax Act may plead not guilty, guilty or, with the consent of the court, nolo contendere. The court may refuse to accept a plea of guilty, and shall not accept such plea or a plea of nolo contendere without first addressing the defendant personally and determining that the plea is made voluntarily with understanding of the nature of the charge and the consequences of the plea. If a defendant refuses to plead or if the court refuses to accept a plea of guilty or if a defendant corporation fails to appear, the court shall enter a plea of not guilty. The court shall not enter a judgment upon a plea of guilty unless it is satisfied that there is a factual basis for the plea.
(Source: P.A. 78-267.)