public static function updateNetworks($networks = array())
    {
        $request = array();

        foreach ($networks as $network) {
            if ($network instanceof \Didww\API2\PSTNNetwork) {

                $request[] = array(
                    "network_prefix" => trim($network->getNetworkPrefix()),
                    "sell_rate" => $network->getSellRate()
                );


            } else {
                throw  new PSTNNetworkException("PSTNNetwork expected but type " .
                    \Didww\Utils\Util::getType($network) .
                    " found");
            }
        }


        self::updateNetworksFromArray($request);
    }