#!/usr/bin/perl --

use strict;
use warnings;

use Data::Dumper;

my %one = ( a => { b => { c => { d => { 6 } } } } );

print Dumper( \%one, $one{a}{b}{c} );

my $none = $one{a}{b}{c} ;
for my $k( keys %$none ){
    $none->{"$k$k"} = "$k$k";
}

print Dumper( \%one);
__END__
$VAR1 = {
          'a' => {
                   'b' => {
                            'c' => {
                                     'd' => {
                                              '6' => undef
                                            }
                                   }
                          }
                 }
        };
$VAR2 = $VAR1->{'a'}{'b'}{'c'};
$VAR1 = {
          'a' => {
                   'b' => {
                            'c' => {
                                     'dd' => 'dd',
                                     'd' => {
                                              '6' => undef
                                            }
                                   }
                          }
                 }
        };
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