/**
  *
  * @return \Entity\Session  
  */
 public static function current_session()
 {
     static $result = false;
     if ($result === false) {
         $repo = \Entity\Session::repository();
         $session_id = api_get_session_id();
         $result = $repo->find($session_id);
     }
     return $result;
 }