code: private function getPv($calcId)
      {
          $query = $this->qbGetPv->build();
          $conn = $query->getConnection();
          $bind = [QBldGetPv::BND_CALC_ID => $calcId];
          $data = $conn->fetchAll($query, $bind);
          $result = $this->hlpDwnlTree->mapValueById($data, QBldGetPv::A_CUST_ID, QBldGetPv::A_PV);
          return $result;
      }
docs: Get PV that are debited inside 'PV Write Off' operation related for the $calcId.
  @param int $calcId
  @return array