django oscar invoice pdf generation

Question

Hi I am trying to set up invoice generation for django oscar. I have found a useful link https://groups.google.com/forum/#!topic/django-oscar/sg1qtyuu32Q (two main links from this google groups are https://gist.github.com/elbaschid/8722203 and https://gist.github.com/elbaschid/8776935)

but I am having an issue trying to set this up.

I saved my templates as suggested in the link and the below is the code under OrderListView:

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

However this gives me an error of

 AttributeError at /dashboard/orders/
'OrderListView' object has no attribute 'packing_slip_template'

The path for the template is 'dashboard/orders/order_packing_slip.html'

I also added a button on order_list.html by adding the below code:

  <button style="margin-right:10px" type="submit" class="btn w3-black w3-hover-dark-gray" name="action" value="generate_packing_slips" data-loading-text="{% trans 'Submitting...' %}">{% trans "Download" %}</button>

I would be grateful if you have any suggestions for the solutions!

Many Thanks