get_object_or_404 on model instance raise ValueError

[Vitaliy Yelnik]

from django.shortcuts import get_object_or_404
from django.db.models.base import ModelBase
from django.contrib.contenttypes.models import ContentType

def test_get_object_or_404():
    # print "True"
    print isinstance(ContentType, ModelBase)

    # print False
    print isinstance(ContentType(), ModelBase)

    # print "<ContentType: content type>"
    print get_object_or_404(ContentType, id=1)

    # raise ValueError: Object is of type 'ContentType', but must be a Django Model, Manager, or QuerySet
    print get_object_or_404(ContentType(), id=1)

In Django 1.4 exception does not occur.

[Tim Graham]

If passing a model instanced actually worked in the past, it was undocumented behavior (see ​Required Arguments of get_object_or_404 and I don't think we're going to make a change to restore that behavior. The change was ticket #19432.