I'm getting values from an API request, and store them into `String` variables to be added to a `List<String>`. When printing this variables prints are fine, but then I get `NoSuchMethodError: The method 'add' was called on null.` when adding them to the list.
Does it mean that I'm not really converting them into strings?
Can you spot what I'm doing wrong ?

As always many thanks for your time and help.

This is the method:

```
Future<List<String>> getCityDb(String isoLocationDb) async {
    print('getCityDb called');

    // namePrefix
    final String request =
        'https://wft-geo-db.p.rapidapi.com/v1/geo/cities?namePrefix=bologna&languageCode=IT'; //&types=ADM2'; // working

    var response = await get(Uri.encodeFull(request), headers: {
      'x-rapidapi-host': 'wft-geo-db.p.rapidapi.com',
      'x-rapidapi-key': apiKey,
    });

    if (response.statusCode == 200) {    
      var jsonResponse = convert.jsonDecode(response.body);
      List<dynamic> properties = jsonResponse['data'];
      print('properties are $properties');

      String name = properties.first['name'].toString();
      String region = properties.first['region'].toString();
      String country = properties.first['country'].toString();

//      print(' getCityDb ${jsonResponse.runtimeType} : $jsonResponse');
      print('getCityDb jsonResponse name is :$name');
      print('getCityDb jsonResponse region is :$region');
      print('getCityDb jsonResponse country is: $country');

      List<String> cityDb;
      cityDb.add(name);
      cityDb.add(region);
      cityDb.add(country);
      return cityDb;
    } else {
      print('getCityDB() Request failed with status: ${response.statusCode}.');
    }
  }

```

And this is the console print:

```
flutter: getCityDb called
flutter: properties are [{id: 148826, wikiDataId: Q1891, type: CITY, city: Bologna, name: Bologna, country: Italia, countryCode: IT, region: Emilia-Romagna, regionCode: 45, latitude: 44.493888888, longitude: 11.342777777}, {id: 3029926, wikiDataId: Q18488439, type: CITY, city: Bolognana, name: Bolognana, country: Italia, countryCode: IT, region: Toscana, regionCode: 52, latitude: 44.04018, longitude: 10.47244}, {id: 63950, wikiDataId: Q50839, type: CITY, city: Bolognano, name: Bolognano, country: Italia, countryCode: IT, region: Abruzzo, regionCode: 65, latitude: 42.216666666, longitude: 13.966666666}, {id: 66955, wikiDataId: Q18478734, type: CITY, city: Bolognano-Vignole, name: Bolognano-Vignole, country: Italia, countryCode: IT, region: Trentino-Alto Adige, regionCode: 32, latitude: 45.91196, longitude: 10.90497}]
flutter: getCityDb jsonResponse name is :Bologna
flutter: getCityDb jsonResponse region is :Emilia-Romagna
flutter: getCityDb jsonResponse country is: Italia
flutter: Erros is NoSuchMethodError: The method 'add' was called on null.

```