     }
     
     // MARK: Keyboard
+    
     func addDoneButtonToKeyboard() {
         let numberToolbar = UIToolbar(frame: CGRectMake(0, 0, self.view.frame.size.width, 50))
         numberToolbar.barStyle = UIBarStyle.Default

}

// MARK: - UITextFieldDelegate
extension MainViewController : UITextFieldDelegate {
    
    func textFieldDidEndEditing(textField: UITextField) {


    
    // MARK: Helpers
    
    func updateTipPersentLabel() {
        let percentValue = Int(tipPercentSlider.value)
        tipPercentLabel.text = "Tip (\(percentValue)%)"
