def unique_question_codes
      codes = @survey.versions.map(&:question_codes).flatten.uniq
      codes.map do |code|
        session_fields.include?(code) ? "answer_#{code}" : code
      end
    end
def unique_question_codes
      codes = @survey.versions.map(&:question_codes).flatten.uniq
      codes.map do |code|
        session_fields.include?(code) ? "answer_#{code}" : code
      end
    end
It could be possible that an answer code equals a session field. We add "answer_" in that case so that we get uniqe question codes for sure