def index(request):
    if request.method == "POST":
        form = InvitationForm(request.POST)
        if form.is_valid():
            to_emails = form.cleaned_data['to_email']
            # TODO: handle error cases
            send_mail(
                'Subject',
                'Our message',
                form.cleaned_data['from_email'],
                to_emails
            )
            return redirect(reverse('invites_thanks') + '?num=%d' % len(to_emails))
    else:
        form = InvitationForm()

    return render_to_response(
        'invites/index.html',
        {
            'invitation_form': form,
        },
        context_instance=RequestContext(request)
    )