Setting NSUnderlineStyle causes unrecogognized selector exception : <p>I am trying to underline a string with NSAttributed string. For some reason, my lines cause the exception: </p>

<pre><code>-[_SwiftValue _getValue:forType:]: unrecognized selector sent to instance   
</code></pre>

<p>The result is supposed to be used for a UILabel within a UITableView and is created as needed.</p>

<p>This is the code:</p>

<pre><code>attributedString = NSMutableAttributedString(string: message)

if let actor = event.actor {
   let attributes = [NSUnderlineStyleAttributeName:NSUnderlineStyle.styleSingle]
   var attributedActorString = NSMutableAttributedString(string: actor.shirtName, attributes: attributes)
   attributedActorString.insert(NSAttributedString(string: " "), at: 0)
   attributedActorString.append(NSAttributedString(string: ". "))                               attributedActorString.append(attributedImageStringForUrl(event.actor!.portraitImageUrl, indexPath: indexPath))
   attributedString.append(attributedActorString)
}
</code></pre>
