我想使用haruncpi/laravel-id-generator包定制id。我有2个数据将插入数据库。该程序是工作，但这些数据的id是重复的
下面是代码

class ArtisSeeder extends Seeder
{
    public function CustomId() 
    {
        $config = [
            'table' => 'artis', 
            'field' => 'kd_artis',
            'length' => 4, 
            'prefix' => 'A'
        ];

        return IdGenerator::generate($config);
    }

    public function run()
    {
        DB::table('artis')->insert([
            [
                'kd_artis' => $this->CustomId(),
                'nm_artis' => 'ROBERT DOWNEY',
                'jk' => 'PRIA',
                'bayaran' => 10000000000,
                'award' => 2,
                'negara' => 'AS',
            ], 
            [
                'kd_artis' => $this->CustomId(),
                'nm_artis' => 'ANGELINA JOLIE',
                'jk' => 'WANITA',
                'bayaran' => 700000000,
                'award' => 1,
                'negara' => 'AS',
            ], 
        ]);
    }
}

注意：kd_artis是id。
那么如何使id不重复呢？