What is the effect of section 654 of the California Code of Criminal Procedure when a defendant is convicted of a single crime?

Section 654 provides in pertinent part: "An act or omission that is punishable in different ways by different provisions of law shall be punished under the provision that provides for the longest potential term of imprisonment, but in no case shall the act or omission be punished under more than one provision." ( 654, subd. (a).) "The purpose of section 654 is to prevent multiple punishment for a single act or omission, even though that act or omission violates more than one statute and thus constitutes more than one crime. Although the distinct crimes may be charged in separate counts and may result in multiple verdicts of guilt, the trial court may impose sentence for only one offense -- the one carrying the highest punishment. [Citation.]" (People v. Liu (1996) 46 Cal.App.4th 1119, 1135, fn. omitted.)