code: def dispatch(self, *args, **kwargs):
          self.__line_pk = kwargs.get('pk', None)
          
          return super(LinesUpdateModalBasket, self).dispatch(*args, **kwargs)
docs: if SalesLineBasketOption.objects.filter(line_budget__pk=self.__line_pk).exists():
              self.form_class = LineBasketFormPack
              self.__is_pack = True
          else:
              self.__is_pack = False