title: Swift Protocol: what am i doing wrong?
body: <pre><code>@objc protocol Animal{
  typealias ElementType
  func getSiblings() -&gt;[ElementType]
  func getMother() -&gt; ElementType?
  func getFather() -&gt; ElementType?
  optional func addSibling(sibling:ElementType)
  }    
  </code></pre>
  
  <p>It keep giving me the error message:  method cannot be marked @objc because its result type cannot be represented in Objective-C. Thanks in advance</p>