def logowanie(request):
    if request.method == 'POST':
        user = authenticate(
            username=request.POST.get('id_username', '').strip(),
            password= request.POST.get('id_password', ''),
            )
        if user is None:
            messages.error(request, u'Invalid credentblog.ials')
        else:
            if user.is_active:
                login(request, user)
                return HttpResponseRedirect(request.GET.get('next', '/'))
            else:
                messages.error(request, u'User is not active.')

                return render_to_response('registration/login.html', locals(),
                    context_instance=RequestContext(request))

TypeError: login() missing 1 required positional argument: 'user'

url(r'^login', navigoWeb_views.login, name='log'),

url(r'^log', navigoWeb_views.log, name='log'),