Method correctMinusPrice

public function correctMinusPrice(&$price)
{
    if (isset($price['brutto']) && $price['brutto'] < 0) {
        $price['brutto'] = 0;
        $price['bruttoformat'] = $this->getPriceFormat(0);
    }
    if (isset($price['netto']) && $price['netto'] < 0) {
        $price['netto'] = 0;
        $price['nettoformat'] = $this->getPriceFormat(0);
    }
    if (isset($price['tax']) && $price['tax'] < 0) {
        $price['tax'] = 0;
        $price['taxformat'] = $this->getPriceFormat(0);
    }
    return true;
}