Laravel Livewire error "must not be accessed before initialization"

I try to using Livewire Binding Directly To Model Properties, and i get this error, Anyone help please ? Thank in advance.

Typed property App\Http\Livewire\V2\Settings\Locations::$country must not be accessed before initialization

 class Locations extends Component{
  public Country $country;
  use WithPagination;
  protected $rules = [
    'country.name' => 'required|min:100',
    'country.note' => 'required|min:100',
  ];

  public function SaveCountry(){
    $this->validate();
    $this->country->save();
    $this->reset();
    session()->flash('info','The country have been added successful.');
  }
 public function render(){
    return view('livewire.v2.settings.locations',[
        'countries' => Country::orderBy('order_num','desc')->paginate(10),
    ]);
  }
}

When you define the type of a variable in PHP, you need to provide it a default value.

If your component is creating a Country, you can set it to an empty Country in the mount function:

public function mount()
{
    $this->country = new Country();
}

Alternatively set the public Country $country to be an existing Country.