public function apply_config($config)
    {
        if (!is_array(reset($config)))
            $config = array($config);
        foreach ($config as $entry)
        {
            $pub = new PubControlClient($entry['uri']);
            if (array_key_exists('iss', $entry))
                $pub->set_auth_jwt(array('iss' => $entry['iss']), 
                        $entry['key']);
            $this->clients[] = $pub;
        }
    }