/**
  * Marks library card for deletion so that it can be recovered easily.
  *
  * @param UserCard $userCard
  * @param boolean $shouldBeDeleted
  */
 public function setLibCardDeletionFlag(UserCard $userCard, $shouldBeDeleted)
 {
     $eppn = $userCard->eppn;
     if ($shouldBeDeleted) {
         $userCard->eppn = "DEL_{$eppn}";
     } elseif (substr($eppn, 0, 4) === 'DEL_') {
         $userCard->eppn = substr($eppn, 4);
     }
     $userCard->save();
 }