def save(self):
    promo = PromoCode.objects.filter(code=self.cleaned_data['code'])[0]
    promo.listing = self.listing
    promo.save()
    self.listing.save()
def save(self):
    promo = PromoCode.objects.filter(code=self.cleaned_data['code'])[0]
    promo.listing = self.listing
    promo.save()
    self.listing.save()