Added content_type filtering in Permission querying example.

docs/topics/auth/default.txt

@@ -275,25 +275,32 @@ afterward, in a test or view for example, the easiest solution is to re-fetch
 the user from the database. For example::
 
     from django.contrib.auth.models import Permission, User
+    from django.contrib.contenttypes.models import ContentType
     from django.shortcuts import get_object_or_404
 
+    from myapp.models import BlogPost
+
     def user_gains_perms(request, user_id):
         user = get_object_or_404(User, pk=user_id)
         # any permission check will cache the current set of permissions
-        user.has_perm('myapp.change_bar')
+        user.has_perm('myapp.change_blogpost')
 
-        permission = Permission.objects.get(codename='change_bar')
+        content_type = ContentType.objects.get_for_model(BlogPost)
+        permission = Permission.objects.get(
+            codename='change_blogpost',
+            content_type=content_type,
+        )
         user.user_permissions.add(permission)
 
         # Checking the cached permission set
-        user.has_perm('myapp.change_bar')  # False
+        user.has_perm('myapp.change_blogpost')  # False
 
         # Request new instance of User
         # Be aware that user.refresh_from_db() won't clear the cache.
         user = get_object_or_404(User, pk=user_id)
 
         # Permission cache is repopulated from the database
-        user.has_perm('myapp.change_bar')  # True
+        user.has_perm('myapp.change_blogpost')  # True
 
         ...