[1.3.X] Fixed #15746. Clarified updated list_filter documentation.

            list_display = ('username', 'email', 'first_name', 'last_name', 'is_staff')

            list_filter = ('is_staff', 'is_superuser')

    Fields in ``list_filter`` can also span relations using the ``__`` lookup::

        class UserAdminWithLookup(UserAdmin):

            list_filter = ('groups__name')

    The above code results in an admin change list page that looks like this:

        .. image:: _images/users_changelist.png

    (This example also has ``search_fields`` defined. See below.)

    .. versionadded:: 1.3

    Fields in ``list_filter`` can also span relations using the ``__`` lookup::

        class UserAdminWithLookup(UserAdmin):

            list_filter = ('groups__name')

.. attribute:: ModelAdmin.list_per_page

    Set ``list_per_page`` to control how many items appear on each paginated