i want set the navigation hide while scroling tableview,but it doesn't work,i make sure have set the property,why?ios

in some artical,i see "navigationController?.hidesBarsOnSwipe = true",but this is wrong,how to write it for specificly? When i set the property "self.navigationController.hidesBarsOnSwipe = YES;",the navigation doesn't work? what's the matter?please give some ideas.