/**
  * Return # of specific timeslot
  *
  * @param Timeslot $timeslot
  * @return integer
  */
 function getTimeslotNum(Timeslot $timeslot)
 {
     $timeslots = $this->getTimeslots();
     if (is_array($timeslots)) {
         $counter = 0;
         foreach ($timeslots as $object_timeslot) {
             $counter++;
             if ($timeslot->getId() == $object_timeslot->getId()) {
                 return $counter;
             }
         }
     }
     return 0;
 }