Laravel Eloquentでモデルを削除するときに関連する行を自動的に削除する方法は?

namespace App\Models;

use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    public function photos()
    {
        return $this->has_many('Photo');
    }

    // this is a recommended way to declare event handlers
    protected static function booted()
    {
        static::deleting(function(User $user) { // before delete() method calls this
            $user->photos()->delete();
            // perform additional cleanup if necessary
        });
    }
}