public override IAnswer execute()
        {
            List<Database.Airport> airports = new List<Database.Airport>();
            if (this.City != null) {
                airports = executeOnCity();
            } else if (this.Country != null) {
                airports = executeOnCountry();
            }

            Database.AirlineRequest alr = new Database.AirlineRequest();
            List<Airport> resultAirports = new List<Airport>();
            foreach(Database.Airport a in airports){
                Database.CityRequest cir = new Database.CityRequest();
                Database.CountryRequest cor = new Database.CountryRequest();
                Database.City ci = cir.fetchFromID(a.city)[0];
                Database.Country co = cor.fetchFromID(a.country)[0];

                Country country = new Country(co.name);

                List<Airline> airlines = new List<Airline>();
                foreach(int airline in a.company){
                    Database.Airline al = alr.fetchFromID(airline)[0];
                    airlines.Add(new Airline(Name: al.name, Code: al.code));
                }
                resultAirports.Add(new Airport(Name: a.name, Code: a.code, City: new City(ci.name, country), Airlines: airlines));
            }

            return new AnswerGetAirports(resultAirports);
        }
        private List<Flight> adapt(List<Database.Flight> dfs)
        {
            Database.FlightTemplateRequest ftr = new Database.FlightTemplateRequest();
            Database.AirlineRequest alr = new Database.AirlineRequest();
            Database.AirplaneRequest apr = new Database.AirplaneRequest();
            Database.LocationRequest lr = new Database.LocationRequest();
            Database.SeatRequest sr = new Database.SeatRequest();
            Database.ClassRequest cr = new Database.ClassRequest();
            Database.CountryRequest cor = new Database.CountryRequest();
            Database.CityRequest cir = new Database.CityRequest();
            Database.AirportRequest ar = new Database.AirportRequest();

            List<Flight> fs = new List<Flight>();
            foreach(Database.Flight f in dfs){
                Database.FlightTemplate ft = ftr.fetchFromID(f.template)[0];
                Database.Airline airline_ = alr.fetchFromID(ft.airline)[0];

                Airline airline = new Airline(Name: airline_.name, Code: airline_.code);
                FlightTemplate template = new FlightTemplate(ft.digits, airline);

                Database.Location l = lr.fetchFromID(f.location)[0];
                Database.Airport startAirport_ = ar.fetchFromID(l.start_airport)[0];
                Database.Airport destinationAirport_ = ar.fetchFromID(l.destination_airport)[0];

                Country startCountry = new Country(cor.fetchFromID(startAirport_.country)[0].name);
                Country destinationCountry = new Country(cor.fetchFromID(destinationAirport_.country)[0].name);

                City startCity = new City(cir.fetchFromID(startAirport_.city)[0].name, startCountry);
                City destinationCity = new City(cir.fetchFromID(destinationAirport_.city)[0].name, destinationCountry);

                Airport startAirport = new Airport(startAirport_.name, startAirport_.code, startCity);
                Airport destinationAirport = new Airport(destinationAirport_.name, destinationAirport_.code, destinationCity);

                Database.Airplane airplane_ = apr.fetchFromID(f.airplane)[0];

                List<Seat> seats = new List<Seat>();
                foreach(int s in airplane_.seat){
                    Database.Seat seat_ = sr.fetchFromID(s)[0];
                    Database.Class seatClass_ = cr.fetchFromID(seat_.class_)[0];
                    SeatClass seatClass = new SeatClass(seatClass_.name);
                    seats.Add(new Seat(seatClass, seat_.number));
                }

                Airplane airplane = new Airplane(airplane_.type, seats, airplane_.code);

                fs.Add(new Flight(template, f.start, f.end, startAirport, destinationAirport, airplane));
            }

            return fs;
        }