$xml_out = new IO::File(">$filename");
    # 'OUTPUT'	writes to this file
    # 'DATA_MODE'	writes <CRLF> after each line
    # 'DATA_INDENT'	indents each level four spaces
    $xml_writer = new XML::Writer(
        OUTPUT      => $xml_out,
        DATA_MODE   => 'true',
        DATA_INDENT => 4
    );