BigIntegerField not working properly in model

[sig003]

One line description of the issue

I declared a BigIntegerField in a model, but the field actually created by mongodb is an Int32. I want Int64, but it doesn't work. My djongo version is 1.3.6. I want to know if it is a bug or my mistake.

Python script

from djongo import models as djongoModels

class TestModel(models.Model):
   ...
   reservationNumber = djongoModels.BigIntegerField(default=0)
   ...

Traceback