Hi monks, i want to change an xml file tags using XML::Simple for that i convert an xml file to hash and replace the tags via another hash and convert the hash as xml file this is my code using this code i cant get the output file please help me to debug the error

#!/usr/bin/perl
use warnings;
use strict;
use Data::Dumper;
use XML::Simple;
my %xhash=();
my $file= $ARGV[0];
my $simple = XML::Simple->new();
my $xhash   = $simple->XMLin($file);
print Dumper ($xhash);
my %c_hash=('a' => {
                   'addval' => {
                                 'b' => {
                                          'addval' => {
                                                        'e' => {
                                                                 'addv
+al' => {},
                                                                 'repv
+al' => '5'
                                                               },
                                                        'c' => {
                                                                 'addv
+al' => {},
                                                                 'repv
+al' => '3'
                                                               }
                                                      },
                                          'repval' => '2'
                                        },
                                 'd' => {
                                          'addval' => {},
                                          'repval' => '4'
                                        }
                               },
                   'repval' => '1'
                 });

my %repl;  # lookup table: a => 1, etc.
traverse(\%c_hash,
         sub {
             my ($key, $val) = @_;
             $repl{$key} = $val;
         },
         "collect"
);
 #print Dumper \%repl;  # debug

traverse(\%xhash,
         sub {
             my ($key, $val, $href) = @_;
             if (exists $repl{$key}) {
                 my $newkey = $repl{$key};
                 $href->{$newkey} = $val;
                 delete $href->{$key};
             }
         },
         "replace"
);
print Dumper \%xhash;
$simple->XMLout($xhash,
            KeepRoot   => 1,
            OutputFile => 'pets.fixed.xml',
            XMLDecl    => "<?xml version='1.0'?>",
        );

sub traverse {
    my ($hash, $callback, $mode) = @_;
    return unless ref($hash) eq "HASH";
    for my $key (keys %$hash) {
        my $val = $hash->{$key};
        if (ref($val) eq "HASH") {
            traverse($val, $callback, $mode);
            if ($mode eq "collect") {
                if (exists $val->{repval}) {
                    $callback->($key, $val->{repval});
                }
            }
        }
        if ($mode eq "replace") {
            $callback->($key, $val, $hash);
        }
    }
}
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