Django changing models field into views - django

Question

I everyone, I have a problem with a django's view. My goal is to change the 'execute' field into 'True' if newOrder is buy and there is some other sell order with a inferior price. And reverse for sell newOrders. I want to change the 'execute' field for the newOrder and also for the other order (in pairs). That's my code:
views.py
def order(request):
form = OrderForm()
if request.method == 'POST':
form = OrderForm(request.POST)
if form.is_valid():
new_order = form.save()
if new_order.buy is True:
sellOrder = Order.objects.filter(sell=True, execute=False,
price__lte=new_order.price).first().update(execute=True)
new_order.execute = True
sellOrder.save()
else:
buyOrder = Order.objects.filter(buy=True,
execute=False,price__gte=new_order.price).first().update(execute=True)
new_order.execute = True
buyOrder.save()
new_order.profile = request.user
new_order.save()
return redirect('home')
else:
form = OrderForm()
contex = {'form': form}
return render(request, 'app/new_order.html', contex)
models.py
class Profile(models.Model):
_id = ObjectIdField()
user = models.ForeignKey(User, on_delete=models.CASCADE)
wallet = models.FloatField()
class Order(models.Model):
_id = ObjectIdField()
profile = models.ForeignKey(User, on_delete=models.CASCADE)
datetime = models.DateTimeField(auto_now_add=True)
buy = models.BooleanField(blank=True)
sell = models.BooleanField(blank=True)
price = models.FloatField()
quantity = models.FloatField()
execute = models.BooleanField(blank=True)
But something goes wrong. This is the error:
AttributeError at /new_order/
'NoneType' object has no attribute 'update'

Answer 1

sellOrder returns a count of updated rows, not the object updated
sellOrder = Order.objects.filter(sell=True, execute=False,
price__lte=new_order.price).first().update(execute=True)
instead try
sellOrder = Order.objects.filter(sell=True, execute=False,
price__lte=new_order.price).first()
new_order.execute = True
sellOrder.execute = True
sellOrder.save()