Setting animation and labels to btns

btnLabels.swift

   switch index {
        case 0:
            UIView.animate(withDuration: 0.3, animations: {
                self.btnIniciarOUTLET.setTitle("Próximo", for: .normal)
                self.btnIniciarOUTLET.alpha = 1
            })
        case 1:
            UIView.animate(withDuration: 0.3, animations: {
                self.btnIniciarOUTLET.setTitle("Próximo", for: .normal)
                self.btnIniciarOUTLET.alpha = 1
            })
        case 0:
            UIView.animate(withDuration: 0.3, animations: {
                self.btnIniciarOUTLET.setTitle("Entendi", for: .normal)
                self.btnIniciarOUTLET.alpha = 1
            })
        default:
            break
        }