(e)
Tetrahydrocannabinols. If a person possesses or attempts to possess tetrahydrocannabinols included under s.
961.14 (4) (t), or a controlled substance analog of tetrahydrocannabinols, the person may be fined not more than $1,000 or imprisoned for not more than 6 months or both upon a first conviction and is guilty of a Class I felony for a 2nd or subsequent offense. For purposes of this paragraph, an offense is considered a 2nd or subsequent offense if, prior to the offender's conviction of the offense, the offender has at any time been convicted of any felony or misdemeanor under this chapter or under any statute of the United States or of any state relating to controlled substances, controlled substance analogs, narcotic drugs, marijuana, or depressant, stimulant, or hallucinogenic drugs.