protected function getCsvDelimiter(PropertyMappingConfigurationInterface $configuration = null)
    {
        if ($configuration === null) {
            return self::DEFAULT_CSV_DELIMITER;
        }

        $csvDelimiter = $configuration->getConfigurationValue(StringConverter::class, self::CONFIGURATION_CSV_DELIMITER);
        if ($csvDelimiter === null) {
            return self::DEFAULT_CSV_DELIMITER;
        } elseif (!is_string($csvDelimiter)) {
            throw new InvalidPropertyMappingConfigurationException('CONFIGURATION_CSV_DELIMITER must be of type string, "' . (is_object($csvDelimiter) ? get_class($csvDelimiter) : gettype($csvDelimiter)) . '" given', 1404229000);
        }

        return $csvDelimiter;
    }