The classifications of municipalities which existed prior to the time this title goes into effect—first-class cities, second-class cities, unclassified cities, and towns—and the restrictions, limitations, duties and obligations specifically imposed by law upon such classes of cities and towns, shall have no application to charter code cities, but every charter code city, by adopting such classification, has elected to be governed by its charter and by the provisions of this title, with the powers thereby granted.