code: private function getCalcData()
      {
          /**
           * Create Unqualified Process (Downgrade) calculation.
           */
          $req = new AGetPeriodRequest();
          $req->setBaseCalcTypeCode(Cfg::CODE_TYPE_CALC_PV_WRITE_OFF);
          $req->setDepCalcTypeCode(Cfg::CODE_TYPE_CALC_UNQUALIFIED_PROCESS);
          /** @var AGetPeriodResponse $resp */
          $resp = $this->servPeriodGet->exec($req);
          /** @var \Praxigento\BonusBase\Repo\Data\Calculation $writeOffCalc */
          $writeOffCalc = $resp->getBaseCalcData();
          /** @var \Praxigento\BonusBase\Repo\Data\Calculation $pwWriteOffCalc */
          $processCalc = $resp->getDepCalcData();
          /**
           * Compose result.
           */
          $result = [$writeOffCalc, $processCalc];
          return $result;
      }
docs: Get data for periods & calculations.
  
  @return array [$writeOffCalc, $writeOffPeriod, $processCalc]
  @throws \Exception