protected function fileIterator($directoryPath)
    {
        $this->typeCheck->fileIterator(func_get_args());

        return new RecursiveIteratorIterator(
            new RecursiveDirectoryIterator(
                $directoryPath,
                FilesystemIterator::FOLLOW_SYMLINKS |
                FilesystemIterator::SKIP_DOTS
            )
        );
    }
protected function fileIterator($directoryPath)
    {
        $this->typeCheck->fileIterator(func_get_args());

        return new RecursiveIteratorIterator(
            new RecursiveDirectoryIterator(
                $directoryPath,
                FilesystemIterator::FOLLOW_SYMLINKS |
                FilesystemIterator::SKIP_DOTS
            )
        );
    }
@param string $directoryPath

@return RecursiveIteratorIterator