un filter fuera de lo comun

gistfile1.py

# coding: utf-8
from django.template import Library
from django.db import models
from django.utils.translation import ugettext as _

register = Library()

def estado_filter(cl):
    if not getattr(cl.model_admin, 'estado_filter', False):
        return
    field_name = cl.model_admin.estado_filter
    alpha_field = '%s__exact' % field_name
    alpha_lookup = cl.params.get(alpha_field, '')
    link = lambda d: cl.get_query_string(d) 
    all_letters = {'4':'En revisión','1':'Autorizado','3':'Rechazado','2':'Facturación',}
    lista = ['4','1','3','2']
    choices = [{
        'link': link({alpha_field: letter}),
        'title': all_letters[letter], 
        'active': letter == alpha_lookup,
        'has_entries': True,} for letter in lista]
    all_letters = [{
        'link': cl.get_query_string(None,alpha_field),
        'title': _('All'),
        'active': '' == alpha_lookup,
        'has_entries': True
    },]
    return {'choices': all_letters + choices}
estado_filter = register.inclusion_tag('admin/estado_filter.html')(estado_filter)