Cosa loca de Django

locura1.py

invoice_6_contract_5_items = invoice_6.invoice_items.filter(
   contract=self.contract5
)
print invoice_6_contract_5_items.first().id, invoice_6_contract_5_items.last().id
print invoice_6_contract_5_items[0].id, invoice_6_contract_5_items[1].id

output >>

22 22
22 23

locura2.py

In [1]: ii = InvoiceItem.objects.all()[:2]

In [2]: i = Invoice.objects.all()[:2]

In [3]: i.first().id, i.last().id
Out[3]: (23, 17)

In [4]: i.values_list('id', flat=True)
Out[4]: [23, 22]

In [5]: i.first().id, i.last().id
Out[5]: (23, 17)

In [6]: i
Out[6]: [<Invoice: 7>, <Invoice: 6>]

In [7]: i[0].id, i[1].id
Out[7]: (23, 22)

In [8]:  Invoice.objects.all().last()
Out[8]: <Invoice: 1>

In [9]:  Invoice.objects.all().last().id
Out[9]: 17

In [10]: type(Invoice.objects.all()[:2])
Out[10]: django.db.models.query.QuerySet

In [11]: type(Invoice.objects.all())
Out[11]: django.db.models.query.QuerySet