Fixed -- Doc'd the return value for GenericForeignKey when the related object is deleted.
@@ -335,6 +335,13 @@ creating a ``TaggedItem``::
>>> t.content_object
<User: Guido>
+If the related object is deleted, the ``content_type`` and ``object_id`` fields
+remain set to their original values and the ``GenericForeignKey`` returns
+``None``::
+
+ >>> guido.delete()
+ >>> t.content_object # returns None
+
Due to the way :class:`~django.contrib.contenttypes.fields.GenericForeignKey`
is implemented, you cannot use such fields directly with filters (``filter()``
and ``exclude()``, for example) via the database API. Because a
