Wis. Stat. § 65.01

The common council of any city of the 2nd, 3rd, or 4th class may by ordinance adopted by three-fourths of all its members accept the provisions of ss. 65.02, 65.025, 65.03 and 65.04 which when so accepted shall be in full force and effect as to any such city. Except as above provided ss. 65.01 to 65.20 shall apply only to cities of the 1st class.