Illuminate\Database\Eloquent\Model::newPivot PHP Method

    public function newPivot(Model $parent, array $attributes, $table, $exists, $using = null)
    {
        if ($using) {
            return new $using($parent, $attributes, $table, $exists);
        }
        return new Pivot($parent, $attributes, $table, $exists);
    }

 public function newPivot(Model $parent, array $attributes, $table, $exists)
 {
     if ($parent instanceof Order) {
         return new ProductPrice($parent, $attributes, $table, $exists);
     }
     return parent::newPivot($parent, $attributes, $table, $exists);
 }