django: TypeError: l'objet 'tuple' n'est pas appelable

Obtenir une erreur de type 'tuple' objet n'est pas appelable. Aucune idée de ce que cela pourrait être? (ne vous inquiétez pas à propos de l'indentation. Il copie de bizarre.) Je suis en train de créer des choix basés sur PackSize de storeliquor.

Views.py:

def storeliquor(request, store_id, liquor_id):        
a = StoreLiquor.objects.get(StoreLiquorID=liquor_id)
s = Store.objects.get(StoreID=store_id)
x = Order.objects.get(storeID=s, Active=True)
y = a.OffPremisePrice
c = a.BottleSize
g = request.POST.get('OrderAmount', '')
b = a.PackSize
h = b*2
d = b*3
e = b*4
r = b*5
if c == "1750 ML":
pack_size = (
('1', '1')
('3', '3')
(b, b)
(h, h)
(d, d)
(e, e)
(r, r)
)
elif c == "1000 ML":
pack_size = (
('1', '1')
('3', '3')
('6', '6')
(b, b)
(h, h)
(d, d)
(e, e)
(r, r)
)
elif c == "750 ML":
pack_size = (
('1', '1')
('3', '3')
('6', '6')
(b, b)
(h, h)
(c, d)
(e, e)
(r, r)
)     
elif c == "375 ML":
pack_size = (
('3', '3')
('6', '6')
('12', '12')
(b, b)
(h, h)
(d, d)
(e, e)
(r, r)
)        
elif c == "200 ML":
pack_size = (
('12', '24')
('24', '24')
(b, b)
(c, c)
(c, d)
(e, e)
(r, r)
) 
else:
pack_size = (
(b, b)
(c, c)
(c, d)
(e, e)
(r, r)
)        
if request.method == "POST":
f = AddToOrderForm(request.POST)
if f.is_valid():
z = f.save(commit=False)
z.TotalPrice = (float(y)) * (float(g))
z.storeliquorID = a
z.orderID = x
z.save()        
return HttpResponseRedirect('/stores/get/%s' % store_id)
else:
f = AddToOrderForm()
f.fields['OrderAmount'].choices = pack_size      
args = {}
args['liquor'] = a
args['s'] = s
args['form'] = f   
return render(request,'storeliquor.html', args)

Modèles de fichier:

class LiquorOrder(models.Model):
LiquorOrderID = models.AutoField(primary_key=True)
storeliquorID = models.ForeignKey(StoreLiquor)
orderID = models.ForeignKey(Order)
OrderAmount = models.CharField('Order Amount', max_length=3)
TotalPrice = models.DecimalField('Total Price', max_digits=5, decimal_places=2)
StorePrice = models.DecimalField('Store Price', max_digits=5, decimal_places=2)

Formes de fichier:

class AddToOrderForm(forms.ModelForm):
class Meta:
model = LiquorOrder
fields = ('OrderAmount', 'StorePrice')

source d'informationauteur RuSs