AttributeError: 'NoneType' object has no attribute 'attname' (Django)

As for me, I had:

 def __init__(self):
        return self.title

instead of

 def __str__(self):
        return self.title

so I had mistyped __init__ in place of __str__

to reformulate the previous and make it more explicit: this error is due to an __init__ method that is not referencing its parent class. make sure your __init__ method is defined like this:

def __init__(self, *args, **kwargs):
    super().__init__(*args,**kwargs)
    ...

It took about 90 minutes to find this. I only found it after I had taken out of my model first the abstract supermodel, then all relationship fields, then all-but-one data fields, until only a single IntegerField was left. The create still didn't work.

At that point I called create on some other simple model class MyModel2 in exactly the same test context. It worked (like the idiomatic breeze).

So what the hell was special about MyModel??

And then it dawned on me: MyModel had an __init__ method; most of my other models did not. So look at that. And bang your forehead: I simply had forgotten the mandatory (in Python 3 style)

super().__init__(*args, **kwargs)

Moral: Don't forget this or you may suffer from a really tough error message.

(Note: If you don't like the style of this post, I am sorry. It was required therapeutic writing for me.)