def _paypal_try_url(self, request, tries=3, context=None):
        """ Try to contact Paypal. Due to some issues, internal service errors
        seem to be quite frequent. Several tries are done before considering
        the communication as failed.

         .. versionadded:: pre-v8 saas-3
         .. warning::

            Experimental code. You should not use it before OpenERP v8 official
            release.
        """
        done, res = False, None
        while (not done and tries):
            try:
                res = urllib2.urlopen(request)
                done = True
            except urllib2.HTTPError as e:
                res = e.read()
                e.close()
                if tries and res and json.loads(res)['name'] == 'INTERNAL_SERVICE_ERROR':
                    _logger.warning('Failed contacting Paypal, retrying (%s remaining)' % tries)
            tries = tries - 1
        if not res:
            pass
            # raise openerp.exceptions.
        result = res.read()
        res.close()
        return result