code: public function getLoggedInAdministrator(): Administrator 
      {
          if (!isset($_SESSION[SlimPostgres::SESSION_KEY_ADMINISTRATOR_ID])) {
              throw new \Exception("No one is logged in");
          }
  
          if (null === $administrator = (AdministratorsEntityMapper::getInstance())->getObjectById($_SESSION[SlimPostgres::SESSION_KEY_ADMINISTRATOR_ID])) {
              unset($_SESSION[SlimPostgres::SESSION_KEY_ADMINISTRATOR_ID]); /** remove for security */
              throw new \Exception("Invalid administrator id ".$_SESSION[SlimPostgres::SESSION_KEY_ADMINISTRATOR_ID]." in session");
          }
  
          return $administrator;
      }
docs: should not be called by resources that don't require authentication