Method correctTotalIfNull

public static function correctTotalIfNull(&$total, $taxKey)
{
    if ($total['netto'] < 0 || $total['netto'] == 0) {
        $total['brutto'] = 0;
        $total['tax'][$taxKey]['tax'] = 0;
        $total['tax'][$taxKey]['netto'] = 0;
        $total['tax'][$taxKey]['brutto'] = 0;
    }
    return true;
}