Introduce `saved_forms` property to `BaseModelFormSet`

[Ram Rachum]

Hi,

Here's something that I use in my code and I'm thinking it might be useful to include in Django by default:

@property
def saved_forms(self):
    if not self.is_bound:
        return ()
    return tuple(form for form in self.forms if (form.instance.pk is not None))

(This is a property of BaseModelFormSet.)

This allows you to access the forms in the formset that were saved.

What do you think? Would this be useful to add to Django?

(I can easily make this code into a patch if you want.)

[Jacob]

This seems somewhat domain-specific; I can't see a good reason to include this in Django. If you think I'm missing something, please start a thread on django-dev and maybe explain a bit more about your motivation?