title: Scala: Filter duplicate names using groupBy, mapValues, and filter?
body: <p>This should be simple, I thought, but I can't get it to work.  I have a case class with a property name.  I want to check to see if their are duplicate names in it...</p>
  
  <pre><code>employees.groupBy(_.name).mapValues(_.size).filter(_._2 == 1).toSeq.isEmpty
  </code></pre>
  
  <p>That doesn't work... Should it?</p>