How to convert textField.text value to Integer and sum two Integers
<blockquote>
  <p>Initialization of immutable value 'textfieldInt' was never used;
  consider replacing with assignment to '_' or removing it  and
  textfield2Int</p>
</blockquote>

<p>I get that warning twice for textfieldInt</p>

<p>This is all the code I have: </p>

<pre><code>class ViewController: UIViewController {

    @IBOutlet weak var textField1: UITextField!
    @IBOutlet weak var textField2: UITextField!
    @IBOutlet weak var output: UILabel!

    @IBAction func calculate(_ sender: AnyObject) {
        let textfieldInt: Int? = Int(textField1.text!)
        let textfield2Int: Int? = Int(textField2.text!)
        let convert = textField1.text! + textField2.text!
        let convertText = String(convert)
        output.text = convertText

}
</code></pre>