function getEndsAt()
 {
     $start = $this->getStartsAt();
     //SLN_Plugin::addLog($this->getId().' duration '.$this->getDuration()->format('H:i'));
     $minutes = SLN_Func::getMinutesFromDuration($this->getDuration());
     //SLN_Plugin::addLog($this->getId().' duration '.$minutes.' minutes');
     if ($minutes == 0) {
         $minutes = 60;
     }
     $start->modify('+' . $minutes . ' minutes');
     return $start;
 }