The licensing provisions of this chapter shall not be applied to animals whose owners are nonresidents temporarily within the City, kennel dogs which are kept or raised in facilities licensed pursuant to the Code of Iowa, as amended, solely for the bona fide purpose of sale and which are kept under constant restraint, animals brought into the City for the purpose of participating in any animal show or animals properly trained to assist persons with disabilities, providing such animals are kept restrained on the owner’s premises and under supervision or control at all times or under leash at all times.