title: Why will Swift not accept this NSCalendar method call?
body: <pre><code>let dateComponents = NSCalendar.currentCalendar().components(.MonthCalendarUnit, fromDate: dateCreated, toDate: NSDate(), options: 0)
  </code></pre>
  
  <p>I'm trying to find the difference between two NSDates in months, but this function will <em>not</em> cooperate. It keeps complaining about "extra argument 'toDate' in call", but it's definitely supposed to be there.</p>