public ActionResult <IEnumerable <Passenger> > GetPartyMembers(int passengerId)
        {
            PassengerParty p = passengerService.GetParty(passengerId);

            if (p == null)
            {
                return(null);
            }
            return(Ok(passengerService.GetPartyMembers(p.PassengerPartyId, passengerId).Select(p => new PassengerDTO(p)).ToList()));
        }
        public ActionResult <int> GetParty(int passengerId)
        {
            PassengerParty p = passengerService.GetParty(passengerId);

            if (p == null)
            {
                return(null);
            }
            return(passengerService.GetParty(passengerId).PassengerPartyId);
        }