Sonata\Exporter\Source\DoctrineORMQuerySourceIterator::getValue PHP Метод

    protected function getValue($value)
    {
        if (is_array($value) || $value instanceof \Traversable) {
            $value = null;
        } elseif ($value instanceof \DateTime) {
            $value = $value->format($this->dateTimeFormat);
        } elseif (is_object($value)) {
            $value = (string) $value;
        }
        return $value;
    }