sub compare_hash_keys {
        my ($h1,$h2) = @_;

        my @k1 = sort keys %$h1;
        my @k2 = sort keys %$h2;

        return @k2 - @k1 if @k1 <=> @k2;
        for (0..$#k1) {
                return $k1[$_] cmp $k2[$_] if $k1[$_] cmp $k2[$_];
        }

        0;
}