src/Http/UploadedFile.php
public static function normalize(array $files)
    {
        $normalized = array();

        foreach ((array) $files as $key => $value) {
            if ($value instanceof UploadedFileInterface) {
                $normalized[$key] = $value;
            } elseif (isset($value['tmp_name']) === true) {
                $normalized[$key] = self::create($value);
            } elseif (is_array($value) === true) {
                $normalized[$key] = self::normalize($value);
            }
        }

        return $normalized;
    }
public static function normalize(array $files)
    {
        $normalized = array();

        foreach ((array) $files as $key => $value) {
            if ($value instanceof UploadedFileInterface) {
                $normalized[$key] = $value;
            } elseif (isset($value['tmp_name']) === true) {
                $normalized[$key] = self::create($value);
            } elseif (is_array($value) === true) {
                $normalized[$key] = self::normalize($value);
            }
        }

        return $normalized;
    }
Parses the $_FILES into multiple \UploadedFile instances.

@param  array $files
@return \Psr\Http\Message\UploadedFileInterface[]