[% IF sort_order == 1 %]
   [% FOREACH key_1 IN my_hash.keys.sort %]
      [% FOREACH key_2 IN my_hash.$key_1.keys.sort %]
         output something
      [%END%]
   [%END%]
[% ELSE %]
   [% FOREACH key_1 IN my_hash.keys.sort.reverse %]
      [% FOREACH key_2 IN my_hash.$key_1.keys.sort.reverse %]
         output something
      [%END%]
   [%END%]
[%END%]