There shall be 2 classes of licenses for persons working on or connecting plumbing with sewers: for plumbers and for drain layers. In either case, the plumber or drain layer shall make application on a special form furnished by the city. An annual license fee of $25 shall be paid to the city through the office of the director of public service and safety at the time the application for either of such licenses is filed, and the director is to issue all licenses hereunder.
('59 Code, § 931.01) Penalty, see § 117.99