protected function normalizeKeyLessArrayProperty(
        array $source,
        $standardProperty,
        $objectClass = null,
        $parentKey = null
    ) {
        $normalized = [];

        foreach ($source as $index => $value) {

            // if value is just a string, it is the standard property
            if (is_string($value)) {
                $value = [
                    $standardProperty => $value,
                ];
            }

            if ($objectClass) {

                $value = $this->makeClearedDataObject($objectClass, $value, $parentKey ? $parentKey . ".{$index}" : null);
            }

            $normalized[] = $value;
        }

        return $normalized;
    }