static function run_layout($layout_name, $param = '')
 {
     $trace = debug_backtrace();
     $trace_info = 'called from ' . basename($trace[0]['file']) . ' line ' . $trace[0]['line'];
     self::debug("run_layout({$layout_name}" . (strlen($param) ? ",{$param}" : '') . ") {$trace_info}", self::DEBUG_LEVEL_BASICS);
     return parent::run_layout($layout_name, $param);
 }