def listAttachments(self, oid):
        """ list attachements for a given OBJECT ID """
        url = self._url + "/%s/attachments" % oid
        params = {
            "f":"json"
        }
        return self._get(url, params,
                            securityHandler=self._securityHandler,
                            proxy_port=self._proxy_port,
                            proxy_url=self._proxy_url)
list attachements for a given OBJECT ID