title: Swift Selectors with UILocalizedIndexedCollation
body: <p>For the past few months, I've been using a UILocalizedIndexedCollation to sort a UITableView by a core data property "lastName" on a User NSObject.
  My current code to determine the section for each user looks like this:</p>
  
  <pre><code>addUserObject.section = self.collation.sectionForObject(user, collationStringSelector: Selector("lastName"))
  </code></pre>
  
  <p>However, in Xcode 7.3, I get a compiler warning:</p>
  
  <pre><code>No method declared with Objective-C selector 'lastName'
  </code></pre>
  
  <p>My first thought was to use the new Selector formatting, like so:</p>
  
  <pre><code>Selector(User.lastName)
  </code></pre>
  
  <p>But this generates an error:</p>
  
  <pre><code>Instance member 'lastName' cannot be used on type 'User'
  </code></pre>
  
  <p>The code works fine as-is, but I'd like to get rid of the warning in the 'correct' way. Does anyone have any ideas?</p>