UpdateView woes

forms.py

#encoding=utf-8

from django import forms
from django.contrib.localflavor.br.forms import (
    BRCPFField,
    BRCNPJField,
    BRZipCodeField,
    BRPhoneNumberField, #dígitos dos celulares de SP precisam de nova validação
    BRStateSelect,
    ) 
    
from .models import Membro

#class MembroForm(forms.ModelForm):
#    class Meta:
#        model = Membro

class MembroForm(forms.Form):
    #TODO, descobrir se é possível implementar uma condição para escolher CPF ou CNPJ
    #documento = BRCPFField()
    #telefone = BRPhoneNumberField() #TODO: implementar um modelField customizado para acomodar SP.
    #cep = BRZipCodeField()
    logradouro = forms.CharField(max_length=64)
    complemento = forms.CharField(max_length=32)
    bairro = forms.CharField(max_length=32)
    cidade =  forms.CharField(max_length=32)
    #uf =forms.CharField(max_length=4, widget=BRStateSelect,) 

    #class Meta:
    #    model = Membro    

models.py

#encoding=utf-8

from django.db import models

from django.core.urlresolvers import reverse
from django.contrib.auth.models import User
from django.db.models.signals import post_save

TIPOS_DE_PLANO = [
    ('MESA', u'Mesa compartilhada'),
    ('SALA', u'Sala'),
    ('CONTATO', u'Contato'),
]

UNIDADES_DE_PLANO = [
    ('HORA', u'Hora'),
    ('MES', u'Mês'),
]

# Informações adicionais de um usuario
class Membro(models.Model):
    user  = models.OneToOneField(User)
    nome_completo = models.CharField(u'nome',db_index=True, max_length=64)
    documento = models.CharField(max_length=16)
    telefone = models.CharField(db_index=True, max_length=32)
    cep = models.CharField(max_length=16)
    logradouro = models.CharField(u'endereço',max_length=64)
    complemento = models.CharField(max_length=32, blank=True)
    bairro = models.CharField(max_length=32)
    cidade = models.CharField(max_length=32)
    uf = models.CharField(max_length=4)
    #TODO: adicionar um slugfield
    
    @models.permalink
    def get_absolute_url(self):
        return ('membro-detalhe', [str(self.id)]) #parâmetro 1 --> url nomeada

# Vincula as informações de um Membro ao um Usuario
def create_member_profile(sender, instance, created, **kwargs):
    if created:
        Membro.objects.create(user=instance)

post_save.connect(create_member_profile, sender=User)

traceback

Environment:


Request Method: GET
Request URL: http://localhost:8000/membro/atualiza/1/

Django Version: 1.4.1
Python Version: 2.7.3
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.admin',
 'registration',
 'portal',
 'contas',
 'south')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware')


Traceback:
File "/home/nurf/gitcode/openshift/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File "/home/nurf/gitcode/openshift/venv/local/lib/python2.7/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  20.                 return view_func(request, *args, **kwargs)
File "/home/nurf/gitcode/openshift/venv/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  48.             return self.dispatch(request, *args, **kwargs)
File "/home/nurf/gitcode/openshift/venv/local/lib/python2.7/site-packages/django/views/generic/base.py" in dispatch
  69.         return handler(request, *args, **kwargs)
File "/home/nurf/gitcode/openshift/venv/local/lib/python2.7/site-packages/django/views/generic/edit.py" in get
  191.         return super(BaseUpdateView, self).get(request, *args, **kwargs)
File "/home/nurf/gitcode/openshift/venv/local/lib/python2.7/site-packages/django/views/generic/edit.py" in get
  131.         form = self.get_form(form_class)
File "/home/nurf/gitcode/openshift/venv/local/lib/python2.7/site-packages/django/views/generic/edit.py" in get_form
  34.         return form_class(**self.get_form_kwargs())

Exception Type: TypeError at /membro/atualiza/1/
Exception Value: __init__() got an unexpected keyword argument 'instance'

urls.py

# coding: utf-8

from django.conf.urls import patterns, include, url
from django.views.generic.simple import direct_to_template
from django.contrib import admin

from django.dispatch import receiver
from django.contrib.auth import views as auth_views
from registration.forms import RegistrationFormTermsOfService
from registration.forms import RegistrationFormUniqueEmail
from registration.views import activate
from registration.views import register

from django.views.generic import detail
from django.views.generic.edit import UpdateView

from django.contrib.auth.decorators import login_required

from .models import Membro
from .views import AtualizaMembro
from .forms import MembroForm

urlpatterns = patterns('contas.views',
    url(r'^membro/(?P<pk>\d+)/$', detail.DetailView.as_view(
        model=Membro,
        context_object_name='membro',
        template_name='contas/membro_detalhe.html',
        ),
        name='membro-detalhado'),
    url(r'^membro/atualiza/(?P<pk>\d+)/$',
        #r'^membro/atualiza/$',
        login_required(AtualizaMembro.as_view()),
        name='atualiza-membro')
)