protected function valueToCurrency($format, $value)
    {
        if (!$value) {
            return "";
        }
        if (!$this->_localeInfo) {
            return $value;
        }
        $fmtNum = number_format($value, $this->_localeInfo['frac_digits'], $this->_localeInfo['mon_decimal_point'], $this->_localeInfo['mon_thousands_sep']);
        return $this->_localeInfo["currency_symbol"] . $fmtNum;
    }