No person shall park a vehicle upon public property for any of the following principal purposes:
(Code of Iowa, Sec. 321.236 [1])
1. Sale. Displaying such vehicle for sale;
2. Repairing. For lubricating, repairing or for commercial washing of such vehicle except such repairs as are necessitated by an emergency;
3. Advertising. Displaying advertising;
4. Merchandise Sales. Selling merchandise from such vehicle except in a duly established market place or when so authorized or licensed under this Code of Ordinances.