Add Custom Validation in laravel that accept only alphabet and whitespace

AppServiceProvider.php

<!-- 1 -->
<!-- add your costum validation in function boot -->
<!-- location file : app/Providers/AppServiceProvider.php -->
<!-- Don't forget to add : use Illuminate\Support\Facades\Validator -->

/**
 * Bootstrap any application services.
 *
 * @return void
 */

public function boot()
{
    //Add this custom validation rule.
    Validator::extend('alpha_spaces', function ($attribute, $value) {

        // This will only accept alpha and spaces. 
        // If you want to accept hyphens use: /^[\pL\s-]+$/u.
        return preg_match('/^[\pL\s]+$/u', $value); 

    });

}

SomeRequest.php

<!-- 3 -->
<!-- use it as usual -->

public function rules()
{
    return [
        'name'     => 'required|alpha_spaces',
    ];
}

<!-- direct at controller -->

public function store(Request $request)
{
    $this->validate($request, [
        'name'  => 'required|alpha_spaces'
    ]);
}

validation.php

<!-- 2 -->
<!-- Define your custom validation message -->
<!-- location file :  resources/lang/en/validation.php -->

return [

/*
|--------------------------------------------------------------------------
| Validation Language Lines
|--------------------------------------------------------------------------
|
| The following language lines contain the default error messages used by
| the validator class. Some of these rules have multiple versions such
| as the size rules. Feel free to tweak each of these messages here.
|
*/
// Custom Validation message.
'alpha_spaces'         => 'The :attribute may only contain letters and spaces.',

'accepted'             => 'The :attribute must be accepted.',