title: How to disable pasting in a TextField in Swift?
body: <p>I've got a <code>TextField</code> with a <code>numberPad</code> and the function runs only if it contains numbers.</p>
  
  <p>The user will crash the app if they paste letters in the <code>TextField</code> and click OK.</p>
  
  <p>How can I disable pasting in the <code>TextField</code>?</p>