The description of any offense under this chapter in the words of this chapter, or in any words of like effect shall be sufficient in law; and any exception, exemption, provision, excuse or qualification, whether it occurs by way of proviso or in the description of the offense in this article, may be proved by the defendant, but need not be specified or negatived, in the complaint; but if it is so specified or negatived, no proof in relation to the matter so specified or negatived shall be required on the part of the informant or complainant. (Ord. 1145-85 § 119, 1985.)