one => 1,
two => [
         { x => 1,
           y => [ { a => 1,
                    b => 2
                  },
                  { a => 2,
                    b => 3}
                ]
          }
       ]


##</code><code>##

one => 1,
two => [ { x => 1,
           y_a => 1,
           y_b => 2,
         },
         { x => 1,
           y_a => 2,
           y_b => 3
         }
        ]