/**
  * Returns TRUE, if the user is signed up for any event on the specified event's topic
  * 
  * @param int $userID
  * @param int $eventID
  * @return boolean
  */
 public static function isSignedForEventsTopic($userID, $eventID)
 {
     $event = EventDatabaseManager::getEvent($eventID);
     return EventDatabaseManager::isSignedInForTopic($userID, $event->getTopicID());
 }