Best practice for Python & Django constants

It is quite common to define constants for the integer values as follows:

class Task(models.Model):
    CANCELLED = -1
    REQUIRES_ATTENTION = 0
    WORK_IN_PROGRESS = 1
    COMPLETE = 2

    Status = (
        (CANCELLED, 'Cancelled'),
        (REQUIRES_ATTENTION, 'Requires attention'),
        (WORK_IN_PROGRESS, 'Work in progress'),
        (COMPLETE, 'Complete'),
    )

    status = models.IntegerField(choices=Status, default=REQUIRES_ATTENTION)

By moving the constants and Status inside the model class, you keep the module's namespace cleaner, and as a bonus you can refer to Task.COMPLETE wherever you import the Task model.

CANCELED, ATTENTION, WIP, COMPLETE = range(-1, 3)
Status = (
    (CANCELED, 'Cancelled'),
    (ATTENTION, 'Requires attention'),
    (WIP, 'Work in progress'),
    (COMPLETE, 'Complete'),
)

class Task(models.Model):
    status = models.IntegerField(choices=Status, default=CANCELED)

---

Keep in mind that as others noted, the proper way is to put these variables inside your Model class. That's also how the official django example does it.

There is only one reason where you'd want to put it outside the class namespace and that is only if these semantics are equally shared by other models of your app. i.e. you can't decide in which specific model they belong.

Though it doesn't seem like this is the case in your particular example.