In a prosecution for violation of an ordinance or bylaw of a municipal corporation, a copy thereof certified by its clerk to be a lawfully enacted and existing ordinance or bylaw of such municipal corporation shall be prima facie evidence thereof. The allegation that the acts constituting the offense charged are contrary to the form of such ordinance or bylaw, in such case made and provided, shall be a sufficient reference thereto. (Amended 1971, No. 228 (Adj. Sess.), § 28, eff. July 1, 1972.)