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

        $arrayFormat = $configuration->getConfigurationValue(StringConverter::class, self::CONFIGURATION_ARRAY_FORMAT);
        if ($arrayFormat === null) {
            return self::DEFAULT_ARRAY_FORMAT;
        } elseif (!is_string($arrayFormat)) {
            throw new InvalidPropertyMappingConfigurationException('CONFIGURATION_ARRAY_FORMAT must be of type string, "' . (is_object($arrayFormat) ? get_class($arrayFormat) : gettype($arrayFormat)) . '" given', 1404228995);
        }

        return $arrayFormat;
    }