如何让孩子从两个父类继承？

I know it's impossible in PHP, but in Laravel, the default User model inherits from Authenticatable, but I also need it to inherit from a parent class that I created.

Is there a work around to this?

Laravel is not a programming language, it is written in PHP, so as you said:

it's impossible in PHP

You should make your parent class inherit from Authenticatable and inherit from the parent class. Otherwise, use traits.

For people who want to make the default User model of Laravel inherits from their own parent class, here's how I did it:

use App\Models\Classes\BaseModel;
use Illuminate\Notifications\Notifiable;
use Illuminate\Contracts\Auth\Authenticatable;
use Illuminate\Auth\Authenticatable as AuthenticableTrait;

class User extends BaseModel implements Authenticatable
{
    use AuthenticableTrait, Notifiable;