     
     fileprivate func registerObservers() {
         
-        NotificationCenter.default.addObserver(self, selector: #selector(didReceivePreferredContentSizeChanged(_:)), name: Notification.Name.UIContentSizeCategoryDidChange, object: nil)
-        NotificationCenter.default.addObserver(self, selector: #selector(didReceiveKeyboardWillChangeFrame(_:)), name: Notification.Name.UIKeyboardWillChangeFrame, object: nil)
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(didReceivePreferredContentSizeChanged(_:)),
+                                               name: Notification.Name.UIContentSizeCategoryDidChange,
+                                               object: nil)
+        
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(didReceiveKeyboardWillChangeFrame(_:)),
+                                               name: Notification.Name.UIKeyboardWillChangeFrame,
+                                               object: nil)
         
     }
     

        NotificationCenter.default.removeObserver(self)
    }
    
    @objc private func didReceiveKeyboardWillChangeFrame(_ notification: Notification) {
        
        if let userInfo = notification.userInfo,
            let keyboardEndFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue,

    }
    
    
    private func configure() {
        
        #if swift(>=3.0)
