my %HoHoA = (
              'set1' => {
                         'key1_set1' => [ 'some arrays' ],
                         'key2_set1' => [ 'some arrays' ],
                       },

              'set2' => {
                         'key1_set2' => [ 'some arrays' ],
                         'key2_set2' => [ 'some arrays' ],
                       },

              'set3' => {
                         'key1_set3' => [ 'some arrays' ],
                         'key2_set3' => [ 'some arrays' ],
                       },

              'set4' => {
                         'key1_set4' => [ 'some arrays' ],
                         'key2_set4' => [ 'some arrays' ],
                         'key3_set4' => [ 'some arrays' ],
                       },

);