private static function GetAchievementsIDs()
{
if (!self::IsLoaded()) {
self::LoadAchievements();
}
if (!self::$achievement_ids) {
self::$achievement_ids = array();
foreach (self::$achievements_storage as $achievement) {
self::$achievement_ids[] = $achievement['achievement'];
}
}
return self::$achievement_ids;
}