normalizeFiles example

    public static function normalizeFiles(array $files): array
    {
        $normalized = [];

        foreach ($files as $key => $value) {
            if ($value instanceof UploadedFileInterface) {
                $normalized[$key] = $value;
            } elseif (is_array($value) && isset($value['tmp_name'])) {
                $normalized[$key] = self::createUploadedFileFromSpec($value);
            } elseif (is_array($value)) {
                $normalized[$key] = self::normalizeFiles($value);
                continue;
            } else {
                throw new InvalidArgumentException('Invalid value in files specification');
            }
        }

        return $normalized;
    }

    /** * Create and return an UploadedFile instance from a $_FILES specification. * * If the specification represents an array of values, this method will * delegate to normalizeNestedFileSpec() and return that return value. * * @param array $value $_FILES struct * * @return UploadedFileInterface|UploadedFileInterface[] */