/**
  * @param Event $event
  * @return mixed
  */
 public function map($event)
 {
     if (!$event instanceof \GoogleAnalyticsTracker\HitTypes\Event) {
         throw new \UnexpectedValueException("The Event Mapper only accepts Event HitTypes");
     }
     $data = array('t' => \GoogleAnalyticsTracker\HitTypes\Event::TYPE, 'ea' => $event->getAction(), 'ec' => $event->getCategory());
     if ($event->hasLabel()) {
         $data['el'] = $event->getLabel();
     }
     if ($event->hasValue()) {
         $data['ev'] = $event->getValue();
     }
     $data = array_merge($data, parent::map($event));
     return $data;
 }