Auth_OpenID_GenericConsumer::_createCheckAuthRequest PHP Method

    function _createCheckAuthRequest($message)
    {
        $signed = $message->getArg(Auth_OpenID_OPENID_NS, 'signed');
        if ($signed) {
            foreach (explode(',', $signed) as $k) {
                $value = $message->getAliasedArg($k);
                if ($value === null) {
                    return null;
                }
            }
        }
        $ca_message = $message->copy();
        $ca_message->setArg(Auth_OpenID_OPENID_NS, 'mode', 'check_authentication');
        return $ca_message;
    }