public function getUploadedFiles($step, array $pool = null, array $files = null)
    {
        // Result is empty if no files at all are uploaded ...
        $result = [];

        // 1. Get files for this step from pool
        if (null !== $pool && count($pool) > 0) {
            $result = (isset($pool[Doozr_Form_Service_Constant::IDENTIFIER_FILES][$step])) ?
                $pool[Doozr_Form_Service_Constant::IDENTIFIER_FILES][$step] :
                [];
        }

        // 2. Get uploaded files for this step - if any ...
        if (null !== $files && count($files) > 0) {
            $normalizedFiles = $this->extract($files);

            foreach ($normalizedFiles as $key => $value) {
                $result[$key] = $value;
            }
        }

        return $result;
    }