public static function off($class, $name, $handler = null)
    {
        $class = ltrim($class, '\\');
        if (empty(self::$_events[$name][$class])) {
            return false;
        }
        if ($handler === null) {
            unset(self::$_events[$name][$class]);
            return true;
        } else {
            $removed = false;
            foreach (self::$_events[$name][$class] as $i => $event) {
                if ($event[0] === $handler) {
                    unset(self::$_events[$name][$class][$i]);
                    $removed = true;
                }
            }
            if ($removed) {
                self::$_events[$name][$class] = array_values(self::$_events[$name][$class]);
            }

            return $removed;
        }
    }