Django Material With Django Smart Select Error

I'm using django smart select and django material in a project and getting 'NoneType' object is not subscriptable from the page admin\templates\material\fields\django_relatedfieldw

Solution 1:

You have a bug in your code, in line #138 in smart_selects\widgets.py:

File "C:\project\smart_selects\widgets.py"in render
  138.                    "id": attrs['id'],

(The local variable attrs is not a dict. It is None)