      
      - parameter completionHandler: Callback with [Classifier]?
      */
-    public func getClassifiers(completionHandler: ([Classifier]?, NSError?) -> ()) {
+    public func getClassifiers(completionHandler: ([Classifier]?, NSError?) -> Void) {
         
         // construct request
         let request = WatsonRequest(

     - parameter completionHandler: Callback with Classifer?
     */
    public func getClassifier(classifierId: String,
        completionHandler: (Classifier?, NSError?) -> ()) {
            
        // construct request
        let request = WatsonRequest(

     - parameter completionHandler: Callback with Classifier?
     */
    public func createClassifier(trainerMetaURL: NSURL, trainerURL: NSURL,
        completionHandler: (Classifier?, NSError?) -> Void) {
        
        // force token to refresh
        // TODO: can remove this after its handled by WatsonGateway
