Obsolete documentation or I'm missing something?

[NaturalBornCamper]

In the documentation's permissions section,

It says to use these settings to protect every endpoint:

REST_FRAMEWORK = {
    'DEFAULT_PERMISSION_CLASSES': [
        'rest_framework.permissions.IsAuthenticated',
    ]
}

However, this ends up with the error:
'IsAuthenticated' object has no attribute 'authenticate'

Is there something missing from the documentation that would make this work, or maybe it's not valid anymore?

Note that if I add this line in my ViewSet classes instead, it works perfectly:
permission_classes = [IsAuthenticated]