code: public function setCarrier($carrier)
      {
          if (!is_null($carrier) && (strlen($carrier) > 120)) {
              throw new \InvalidArgumentException('invalid length for $carrier when calling OrderShippingTracking., must be smaller than or equal to 120.');
          }
  
          $this->container['carrier'] = $carrier;
  
          return $this;
      }
docs: Sets carrier
  @param string $carrier
  @return $this