Django 2, python 3.4 не может декодировать urlsafe_base64_decode (uidb64)

Я пытаюсь активировать пользователя по электронной почте, работа электронной почты, работа с кодировками, я использовал подход от django1.11, который успешно работал.

В Django 1.11 следующее успешно декодируется до 28, где uidb64 = b'Mjg '

force_text(urlsafe_base64_decode(uidb64))

В django 2 (2, 0, 0, 'final', 0) вышеупомянутый декодирование кода не работает и приводит к ошибке

django.utils.encoding.DjangoUnicodeDecodeError: 'utf-8' codec can't decode byte 0xc8 in position 1: invalid continuation byte. You passed in b'l\xc8\xe0' (<class 'bytes'>)

Я также публикую свои мнения на всякий случай

from django.utils.encoding import force_bytes, force_text
from django.utils.http import urlsafe_base64_encode, urlsafe_base64_decode    
def signup(request):
    if request.method == 'POST':
        form = SignUpForm(request.POST)
        if form.is_valid():
            user = form.save(commit=False)
            user.is_active = False
            user.save()
            # auth_login(request, user)
            message = render_to_string('user_activate_email.html', {
                'user': user,
                'domain': Site.objects.get_current().domain,
                'uidb64': urlsafe_base64_encode(force_bytes(user.pk)),
                'token': account_activation_token.make_token(user),
            })
            mail_subject = 'Activate your blog account.'
            to_email = form.cleaned_data.get('email')
            email = EmailMessage(mail_subject, message, to=[to_email])
            email.send()
            messages.info(
                request, 'Activation link has been sent to your email!')
            # return redirect('home')
            return render(request, 'index.html')
    else:
        form = SignUpForm()
        return render(request, 'user_action.html', {'form': form})


def activate(request, uidb64, token):
    try:
        import pdb;
        pdb.set_trace()
        uid = urlsafe_base64_decode(uidb64).decode()
        user = User.objects.get(pk=uid)
    except(TypeError, ValueError, OverflowError):
        user = None
    if user is not None and account_activation_token.check_token(user, token):

        user.refresh_from_db()
        user.is_active = True

        user.save()
        auth_login(request, user)
        messages.info(request, 'Your account has been activated successfully!')
        return redirect('events:home')
    else:
        messages.info(
            request, 'Activation link is invalid or has been activated')
        return redirect('events:home')

PS: Это просто испытание, прежде чем я буду работать с CBV.

edit: включая трассировку

System check identified no issues (0 silenced).
December 15, 2017 - 05:51:01
Django version 2.0, using settings 'event_management.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
> /home/vipinmohan/django2-0/event/event_management/users/views.py(88)activate()
-> uid = urlsafe_base64_decode(uidb64).decode()
(Pdb) n
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xcc in position 1: invalid continuation byte
> /home/vipinmohan/django2-0/event/event_management/users/views.py(88)activate()
-> uid = urlsafe_base64_decode(uidb64).decode()
(Pdb) n
> /home/vipinmohan/django2-0/event/event_management/users/views.py(90)activate()
-> except(TypeError, ValueError, OverflowError):
(Pdb) n
> /home/vipinmohan/django2-0/event/event_management/users/views.py(91)activate()
-> user = None
(Pdb)