public function getDeviceStates()
    {
        $uri = 'deviceStates';
        $response = $this->client->getEndpoint()->get($uri);

        $deviceStates = [];
        foreach (\GuzzleHttp\json_decode($response->getBody()) as $deviceState) {
            $deviceStates[] = new DeviceState($this->client, $deviceState);
        }

        return $deviceStates;
    }