public function subscribeEmail($email)
 {
     $user_id = $this->getUserIdByEmail($email);
     if ($user_id) {
         $this->courseParticipants->add($user_id, IL_CRS_MEMBER);
         $this->emailsFound[] = $email;
     } else {
         $this->emailsNotFound[] = $email;
     }
 }
 /**
  * add course admin after import file
  * @return 
  */
 protected function afterImport(ilObject $a_new_object)
 {
     global $ilUser;
     $part = new ilCourseParticipants($a_new_object->getId());
     $part->add($ilUser->getId(), ilCourseConstants::CRS_ADMIN);
     $part->updateNotification($ilUser->getId(), 1);
     parent::afterImport($a_new_object);
 }