In Order for @properties to work correctly The category needs to be a subclass of item. when the class just isn't a subclass of object then The 1st time you are trying accessibility the setter it truly tends to make a brand new attribute Using the shorter identify in lieu https://medium.com/@CommercialProjectsGurgaon/invest-in-excellence-with-smart-world-the-edition-gurgaon-4b801f5effbe