Что вызывает эту ошибку в моем коде 'unsupported operand type(s) for +=: 'NoneType' and 'int''.
Я пытаюсь создать инвестиции, а также обновить баланс инвестиций, но получаю эту ошибку NoneType. Ниже приведен код моей модели и представления.
class Investment(models.Model):
user = models.ForeignKey(
User, on_delete=models.CASCADE, null=True, blank=True)
amount = models.IntegerField(null=True)
balance = models.IntegerField(null=True, blank=True)
investment_id = models.CharField(max_length=10, null=True, blank=True)
plan = models.ForeignKey(Plan, on_delete=models.CASCADE, null=True)
active = models.BooleanField(default=True)
created_at = models.DateTimeField(auto_now=True, null=True)
def __str__(self):
return str(self.investment_id)
def create_investment_view(request):
if request.method == 'POST':
investment_form = InvestmentForm(request.POST)
if investment_form.is_valid():
investment = investment_form.save(commit=False)
investment.balance += investment.amount
investment.balance.save()
investment.save()
messages.success(request, 'your investment is successfull')
else:
messages.success(request, 'your investment is not successfull! Try again.')
else:
investment_form = InvestmentForm()
context = {'investment_form': investment_form}
return render(request, 'create-investment.html', context)