'https://www.sandbox.paypal.com/webscr
?cmd=_cart
&upload=1'

def generate_cart_upload_redirect_url(self, **kwargs):

    required_vals = ('business', 'item_name_1', 'amount_1', 'quantity_1')
    self._check_required(required_vals, **kwargs)
    url = ('%s?cmd=_cart&upload=1' % self.config.PAYPAL_URL_BASE)
    additional = self._encode_utf8(**kwargs)
    additional = urlencode(additional)
    return ((url + '&') + additional)
