CalendarTable::getAllSystemCodes

static function getAllSystemCodes()
{
	$reflection = new ReflectionClass(__CLASS__);
	$constants = array_diff($reflection->getConstants(), $reflection->getParentClass()->getConstants());
	return array_filter($constants, function ($element) {
		return strncmp('SYSTEM_CODE_', $element, mb_strlen('SYSTEM_CODE_')) === 0;
	}, ARRAY_FILTER_USE_KEY);
}