TypeError while using django rest framework tutorial

Just to let others know, I kept getting this same error and found that I forgot to include a comma in my REST_FRAMEWORK. I had this:

'DEFAULT_PERMISSION_CLASSES': (
    'rest_framework.permissions.IsAuthenticated'
),

instead of this:

'DEFAULT_PERMISSION_CLASSES': (
    'rest_framework.permissions.IsAuthenticated',
),

The comma defines this as a one-element tuple