Type error: Argument 1 passed to Illuminate\Auth\EloquentUserProvider::validateCredentials() code example

Example: Type error: Argument 1 passed to Illuminate\Auth\EloquentUserProvider::validateCredentials()

use Illuminate\Auth\Authenticatable;
use Illuminate\Contracts\Auth\Authenticatable as AuthenticatableContract;

class Admin extends Model implements AuthenticatableContract {

    use Authenticatable;
}