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
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
This method simplify results structure,
 it sets only one level of nesting
 by leaving parents only with collection as child