Django model latest() method

The get() function of the Model Manager returns an instance of the Model itself.

The latest() function you mention belongs to the QuerySet class. Calling .filter(), .all(), .exclude() etc, all return a QuerySet.

What you're likely looking for is to first filter for the specific user, then get the latest result by 'id':

rule = Rule.objects.filter(user=user).latest('id')

See here for the docs on querying models