chek present modaly or phus in swift, but idont know what for? : 

> this code i got from my friend. but i don't know how it work. i hope some one in here can help me to explain this code. because this code i would explain to my teacher

        private func isModal() -> Bool {
        if self.presentingViewController != nil {
            return true
        } else if self.navigationController?.presentingViewController?.presentedViewController == self.navigationController  {
            return true
        } else if self.tabBarController?.presentingViewController is UITabBarController {
            return true
        }
        
        return false
    }

> thanks :D 