public function delete($uri = null)
    {
        $this->uri = (isset($uri)) ? (string)$uri : $this->uri;
        try {
            $params = array('uri' => $this->uri);
            $request = new RESTRequest('DELETE', 'documents', $params);
            $this->response = $this->client->send($request);
        } catch(\Exception $e) {
            $this->logger->error(  $e->getMessage() . ' in ' . $e->getFile() . ' on line ' . $e->getLine() );
        }
        return $this;
    }