code: protected static function makePricingOptionFareFamilyOverride($fareFamily)
      {
          $opt = [];
  
          if ($fareFamily !== null) {
              $po = new PricingOptionGroup(PricingOptionKey::OPTION_FARE_FAMILY);
              $po->optionDetail = new OptionDetail([['FF' => $fareFamily]]);
  
              $opt[] = $po;
          }
  
          return $opt;
      }
docs: Load fare-family pricing option and return it.
  
  @param string $fareFamily input fare-family, e.g. "CLASSIC"
  @return PricePnr13\PricingOptionGroup[]