Thank you. I didn't know there is a special operator like this one. Another small question if you may. Is it possible to insert the data into two hash at the same line? something like:

        (%{$one},%{two}) = 
        (
            data => { ( %{ $data{data} }, %{ $one->{data} // {} } ) },
            total => do
            {
                my %total;
                for my $href ( $one->{total}, $data{total} ) {
                    $total{$_} += $href->{$_} for keys %{ $href };
                }
            \%total;
            }
        );
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