def result
      strings = @groups.map { |repeater| repeater.public_send(__callee__) }
      RegexpExamples.permutations_of_strings(strings).map do |result|
        GroupResult.new(result, group_id)
      end
    end
def result
      strings = @groups.map { |repeater| repeater.public_send(__callee__) }
      RegexpExamples.permutations_of_strings(strings).map do |result|
        GroupResult.new(result, group_id)
      end
    end
Generates the result of each contained group
 and adds the filled group of each result to itself