public function getNumberFormatCode($styleId)
{
$stylesAttributes = $this->getStylesAttributes();
$styleAttributes = $stylesAttributes[$styleId];
$numFmtId = $styleAttributes[self::XML_ATTRIBUTE_NUM_FMT_ID];
if ($this->isNumFmtIdBuiltInDateFormat($numFmtId)) {
$numberFormatCode = self::$builtinNumFmtIdToNumFormatMapping[$numFmtId];
} else {
$customNumberFormats = $this->getCustomNumberFormats();
$numberFormatCode = $customNumberFormats[$numFmtId];
}
return $numberFormatCode;
}