code: def get_form(self, form_class=None):
          # form_kwargs = super(LineBasketUpdateModal, self).get_form_kwargs(*args, **kwargs)
          form = super(LinesUpdateModalBasket, self).get_form(form_class)
          initial = form.initial
          initial['type_tax'] = self.object.product_final.product.tax.pk
          initial['tax'] = self.object.tax_basket
          initial['price'] = float(self.object.price_base_basket) * (1 + (self.object.tax_basket / 100))
          
          return form
docs: if self.__is_pack:
              options = []
              lang = get_language_database()
  
              for option in SalesLineBasketOption.objects.filter(line_budget__pk=self.__line_pk):
                  initial['packs[{}]'.format(option.product_option.pk)] = option.product_final.pk
                  a = {
                      'id': option.product_option.pk,
                      'label': getattr(option.product_option, lang).name,
                      'products': list(option.product_option.products_pack.all().values('pk').annotate(name=F('{}__name'.format(lang)))),
                      'selected': option.product_final.pk,
                  }
                  options.append(a)
              # compatibility with GenForeignKey
              initial['packs'] = json.dumps({'__JSON_DATA__': options})