public function cObjGetSingleExt(
        /** @noinspection PhpUnusedParameterInspection */ $name,
        array $configuration,
        /** @noinspection PhpUnusedParameterInspection */ $TyposcriptKey,
        $contentObject
    ) {
        $data = '';
        if (isset($configuration['value'])) {
            $data = $configuration['value'];
            unset($configuration['value']);
        }

        if (!empty($configuration)) {
            $data = $contentObject->stdWrap($data, $configuration);
        }

        if (!array_key_exists('separator', $configuration)) {
            $configuration['separator'] = ',';
        }

        $removeEmptyValues = true;
        if (isset($configuration['removeEmptyValues']) && $configuration['removeEmptyValues'] == 0) {
            $removeEmptyValues = false;
        }

        $listAsArray = GeneralUtility::trimExplode(
            $configuration['separator'],
            $data,
            $removeEmptyValues
        );

        if (!empty($configuration['removeDuplicateValues'])) {
            $listAsArray = array_unique($listAsArray);
        }

        return serialize($listAsArray);
    }