Help for this page
for (sort {$a <=> $b} keys %foo) { print "$_\n"; }
for my $k ( sort {%{ $ref_HoH{$a} } <=> %{ $ref_HoH{$b} } }keys %$r +ef_HoH ) {
for my $k (sort {$a <=> $b } keys %$ref_HoH) {