Select::make('country_id')

                    ->label('Country')

                    ->options(Country::all()->pluck('name', 'id')->toArray())

                    ->reactive()

                    ->afterStateUpdated(function(callable $set) {

                        $set('state_id', null);

                    }),

                    Select::make('state_id')

                    ->label('State')

                    ->options(function (callable $get) {

                        $country = Country::find($get('country_id'));

                        if (!$country) {

                            return State::all()->pluck('name', 'id');

                        }

                        return $country->states->pluck('name', 'id');

                    }),