[Python] How to make group by in django ORM

I've an Order model as below:

class Order(models.Model):
bill = models.ForeignKey(Bill, on_delete=models.PROTECT, null=True, blank=True)
address_from = models.ForeignKey(Address, on_delete=models.PROTECT)
address_to = models.ForeignKey(Address, on_delete=models.PROTECT)


How can I group a queryset from it and iterate in each group like the following:

bill = models.Bill.objects.get(pk=1)
groups = models.Order.objects.all().group_by('address_from', 'address_to')

for group in groups:
group.update(bill = bill)


The point is to assign a specific Bill instance for each group of the orders that have the same address from and address to.

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