#!/perl/bin/perl -w

use strict;
use XML::Twig;

my $field= 'last_ds';
my $twig= new XML::Twig;

$twig->parsefile( "RoamAboutAP_192.168.25.88.xml");
my $root= $twig->root;          
my @ds= $root->children;   

                         
my @sorted= sort {    $b->first_child( $field)->text 
       		  <=> $a->first_child( $field)->text }
           	  @ds;
   
open (XML, ">>test.xml") || warn;
foreach my $attr (@ds) { 

   my $g  = $attr->first_child( 'min')->text;                
   my $blk= $attr->first_child( 'max')->text;  
   my $blg= sprintf( "TEST");          
   my $eblg= new XML::Twig::Elt( 'Average', $blg); 
   $eblg->paste( 'last_child', $attr);            
 }

$twig->set_pretty_print('indented');
$twig->print;  

close XML;