[Fixed]-Expecting value on the json.loads

'b stands for byte-string, if you decode it, it should work

json.loads(output.decode('utf-8'))
{'code': 'pewcndIiD8WcB5MdH+8JOAVJ03xlt92sIUYgs2m2tIGtLohnDHjBP8s8x9/YroJnyrCLcyN6Brwicn9/DS4j9kH8a6gcOKFS1
bpmvdKxJSrmgT0aOz0u16npbt1ldklXx16WEybEN4gKG0DI=', 'success': '1'}