private function httpGet( $path, array $query = array() ){

        $url = new Uri( $this->baseUrl . $path );

        foreach( $query as $name => $value ){
            $url = URI::withQueryValue($url, $name, $value );
        }

        //---

        $request = new Request(
            'GET',
            $url,
            $this->buildHeaders()
        );

        try {

            $response = $this->getHttpClient()->sendRequest( $request );

        } catch (\RuntimeException $e){
            throw new Exception\NotifyException( $e->getMessage(), $e->getCode(), $e );
        }

        //---

        switch( $response->getStatusCode() ){
            case 200:
                return $this->handleResponse( $response );
            case 404:
                return null;
            default:
                return $this->handleErrorResponse( $response );
        }

    }