code: def redirect_to_express(self):
          
          wpp = PayPalWPP(self.request)
          try:
              nvp_obj = wpp.setExpressCheckout(self.item)
          except PayPalFailure:
              warn_untested()
              self.context['errors'] = self.errors['paypal']
              return self.render_payment_form()
          else:
              return HttpResponseRedirect(express_endpoint_for_token(nvp_obj.token))
docs: First step of ExpressCheckout. Redirect the request to PayPal using the
          data returned from setExpressCheckout.