Query RDS's DescribeAccountAttributes API action, and update limits
        with the quotas returned. Updates ``self.limits``.

        We ignore the usage information from the API,

def _update_limits_from_api(self):
        """
        Query RDS's DescribeAccountAttributes API action, and update limits
        with the quotas returned. Updates ``self.limits``.

        We ignore the usage information from the API,
        """
        self.connect()
        logger.info("Querying RDS DescribeAccountAttributes for limits")
        lims = self.conn.describe_account_attributes()['AccountQuotas']
        for lim in lims:
            if lim['AccountQuotaName'] not in self.API_NAME_TO_LIMIT:
                logger.info('RDS DescribeAccountAttributes returned unknown'
                            'limit: %s (max: %s; used: %s)',
                            lim['AccountQuotaName'], lim['Max'], lim['Used'])
                continue
            lname = self.API_NAME_TO_LIMIT[lim['AccountQuotaName']]
            self.limits[lname]._set_api_limit(lim['Max'])
            if len(self.limits[lname].get_current_usage()) < 1:
                self.limits[lname]._add_current_usage(lim['Used'])
        logger.debug('Done setting limits from API.')