src/Amadeus/Client/Struct/Pnr/AddMultiElements/TravellerInfo.php
protected function makePassengerIfNeeded()
    {
        if (count($this->passengerData[0]->travellerInformation->passenger) < 1) {
            $this->passengerData[0]->travellerInformation->passenger[0] = new Passenger(null, null);
        }
    }
protected function makePassengerIfNeeded()
    {
        if (count($this->passengerData[0]->travellerInformation->passenger) < 1) {
            $this->passengerData[0]->travellerInformation->passenger[0] = new Passenger(null, null);
        }
    }
If there is no passenger node at
$travellerInfo->passengerData[0]->travellerInformation->passenger[0]
create one