@login_required
def index(request, abs_id=None):
    ...

    if abs_id:
        instance = get_object_or_404(id=abs_id)
    else:
        instance = None

    if request.method == 'POST':
        instance.status = Status(name='Pending')
        instance.status = presenter=user
        pf = PresentationForm(request.POST, instance=instance)

        if pf.is_valid():
            pf.save()
            return render_to_response('paper_submitted.html', {'user': user},
                context_instance=RequestContext(request))
    else:
        pf = PresentationForm(instance=instance)
        abstracts = Presentation.objects.filter(presenter=user.get_profile())

    return render_to_response('call_for_papers.html', {'presenter_form':pf,
         'abstract_list':abstracts}, context_instance=RequestContext(request))