Python-сообщество

class GoodBrand(models.Model):
    name = models.CharField(max_length=64, verbose_name=u"Название")
    description = models.TextField(verbose_name=u"Описание", blank=True)
    city = models.CharField(max_length=64, verbose_name=u"Город", blank=True)
    def __unicode__(self):
        return "%s - %s" % (self.name, self.city)
    class Meta:
        verbose_name = u"Компания"
        verbose_name_plural = u"Компании"
        
class GoodSeries(models.Model):
    brand = models.ForeignKey(GoodBrand)
    series_name = models.CharField(max_length=250, verbose_name=u"Название")
    description = models.TextField(verbose_name=u"Описание", blank=True)
    def __unicode__(self):
        return "%s - %s" % (self.brand.name, self.series_name)
    class Meta:
        verbose_name = u"Серия товаров"
        verbose_name_plural = u"Серии товаров"
        
class Good(models.Model):
    group_good = models.ForeignKey(GoodSeries, verbose_name=u"Группа")
    title = models.CharField(max_length=250, verbose_name=u"Название")
    barcode = models.CharField(max_length=24, verbose_name=u"Штрих код")
    count = models.IntegerField(max_length=4, verbose_name=u"Остаток")
    image = models.ImageField(upload_to='goods/', verbose_name=u"Фотография",
          blank=True, default="goods/default.png")
    big_image = models.ImageField(upload_to='goods/big/', verbose_name=u"Большая фотография",
          blank=True, default="goods/big/default.png")
    description = models.TextField(verbose_name=u"Описание", blank=True)
    price = models.FloatField(verbose_name=u"Цена", max_length=6)
    volume = models.CharField(max_length=32, verbose_name=u"Объем")

class GoodToBuy(models.Model):
    good_to = models.ForeignKey(Good)
    order = models.ForeignKey(Order)
    count = models.IntegerField(default=0, max_length=3, verbose_name=u"Количество")

class Order(models.Model):
    user = models.ForeignKey(User)
    opened = models.BooleanField(default=True, verbose_name=u"Открыт")
    date_create = models.DateTimeField(auto_now_add=True, verbose_name=u"Дата создания")
    all_price = models.FloatField(default=0, verbose_name=u"Общая стоимость", max_length=8)
    def closed(self):
        self.opened = False
        self.date_create = dt.datetime.now()
        self.all_price = self.get_all_price()
        self.save()
    def get_all_price(self):
        goods = self.goodtobuy_set.all()
        all_price = 0
        for good in goods:
             all_price += good.good_to.price * good.count
        return all_price

for b,c,d in a: #a это как раз список со всеми значениями
        Good.objects.get(barcode=b).update(count=c,price=d)

goods = self.goodtobuy_set.all().select_related()