public function history($category = '', $start = 0, $limit = 100, $failedOnly = false)
    {
        $url = $this->buildUrl('history', [
            'start'       => $start,
            'limit'       => $limit,
            'failed_only' => $failedOnly,
            'category'    => $category
        ]);
        $request = $this->guzzle->request('GET', $url);

        return json_decode($request->getBody(), true)['history'];
    }