Packing slips for Oscar using PISA in the dashboard

views.py

from xhtml2pdf import pisa
from xhtml2pdf.pdf import pisaPDF


class OrderListView(ListView, BulkEditMixin):
    ...

    actions = (
        'generate_packing_slips',
        ...
    )
    ...

    def generate_packing_slips(self, request, orders):
        template = loader.get_template(self.packing_slip_template)
        main_pdf = pisaPDF()

        for order in orders:
            voucher_codes = []
            for discount in order.discounts.all():
                if discount.voucher_code:
                    voucher_codes.append(discount.voucher_code)

            context = RequestContext(request, {
                'order': order,
                'STATIC_ROOT': settings.STATIC_ROOT,
                'voucher_codes': voucher_codes,
            })
            html = template.render(context)
            result = StringIO()

            order_pdf = pisa.pisaDocument(StringIO(html.encode("UTF-8")), result)

            if order_pdf.err:
                messages.error(
                    self.request,
                    _("An problem occured trying to generate the packing slip for "
                      "order #%s") % order.number,
                )
            else:
                main_pdf.addDocument(order_pdf)

        response = HttpResponse(main_pdf.getvalue(), mimetype='application/pdf')
        filename = self.get_packing_slip_filename(orders)
        response['Content-Disposition'] = 'attachment; filename=%s' % filename
        return response

Does this work in python 3?
Also how to define packing_slip_template and get_packing_slip_filename?