my %hash;
for my $pair (split /&/, $old) {
   my ($k,$v) = map {
      s/\+/ /g;
      uri_unescape($_)
   } split /=/, $pair, 2;
   if (exists $hash{$k}) {
      if (ref $hash{$k}) {
         push @{$hash{$k}}, $v;
      } else {
         $hash{$k} = [$hash{$k},$v];
      }
   } else {
      $hash{$k} = $v;
   }
}
return %hash;