public function retrieveNickname($nickname) {
        $query = $this->newNicknameQuery();
        $query->setNickname($nickname);
        try {
            $nickname = $this->getNicknameEntry($query);
        } catch (Zend_Gdata_Gapps_ServiceException $e) {
            // Set the nickname to null if not found
            if ($e->hasError(Zend_Gdata_Gapps_Error::ENTITY_DOES_NOT_EXIST)) {
                $nickname = null;
            } else {
                throw $e;
            }
        }
        return $nickname;
    }