code: def compact_results(items)
        items.map do |subtest|
          subtests = subtest[:subtests]
          if subtests.size > 1
            subtests
          elsif subtests.size == 1
            compact_results(subtests)
          end
        end.flatten.compact
      end
docs: This method simplify results structure,
   it sets only one level of nesting
   by leaving parents only with collection as child