Pimcore\Model\Object\ClassDefinition\Data\Date::getForCsvExport PHP Method

    public function getForCsvExport($object, $params = [])
    {
        $data = $this->getDataFromObjectParam($object, $params);
        if ($data instanceof \Zend_Date) {
            return $data->toString("Y-m-d", "php");
        } elseif ($data instanceof \DateTimeInterface) {
            return $data->format("Y-m-d");
        }
        return null;
    }