code: protected static function loadObFees($obFees, $obFeeRefs)
      {
          $opt = [];
  
          if (!empty($obFees)) {
              $po = new PricingOptionGroup(PricingOptionKey::OPTION_OB_FEES);
  
              $po->penDisInformation = new PenDisInformation(
                  PenDisInformation::QUAL_OB_FEES,
                  $obFees
              );
  
              if (!empty($obFeeRefs)) {
                  $po->paxSegTstReference = new PaxSegTstReference($obFeeRefs);
              }
  
              $opt[] = $po;
          }
  
          return $opt;
      }
docs: Load OB Fees
  
  @param ObFee[] $obFees
  @param PaxSegRef[] $obFeeRefs
  @return PricingOptionGroup[]