[Answered ]-Custom Django Widgets/Fields: object has no attribute 'attrs'

The problem is that you are calling init on an abstract class.

 super(MyFileField, self).__init__(fields=fields, *args, **kwargs)

But the base class is abstract.

Look at https://docs.djangoproject.com/en/1.8/ref/forms/fields/#multivaluefield

and

Python's super(), abstract base classes, and NotImplementedError