public function getAnnouncementsFromAssociation($aid, $apiServiceFilterContext = null)
    {
        $apiServiceFilterContext = $this->checkApiServiceFilterContext($apiServiceFilterContext, $aid);

        $url = $this->getBaseApiUrl() . '/associations/' . $aid . '/announcements';

        $params = null;

        $xml = $this->queryXml($url, $apiServiceFilterContext);

        $this->checkValidContext($xml->list[self::CO_XML_ATTRIBUT_VALID_CONTEXT]);

        return $xml->list;
    }