python中字符串类型json操作的注意事项

jsonstring1={"results":[{"id":"1","name":"\u9ed8\u8ba4\u5206\u7ec4","policy":"4","timer_scan_setting":"{\"last\":\"10.29.13\",\"setting\":\"fulldisk\",\"type\":\"day\",\"hour\":\"13\"}"},
{"id":"2","name":"\u6d4b\u8bd5\u7684","policy":"1","timer_scan_setting":"{\"last\":\"10.29.15\",\"setting\":\"fulldisk\",\"type\":\"day\",\"hour\":\"15\"}"},{"id":"4","name":"\u4ea7\u54c1\u7ec4","policy":"3","timer_scan_setting":"{\"last\":\"10.8.15\",\"setting\":\"disable\"}"}]}

print jsonstring1.keys()
print jsonstring1['results'][0]['policy']

jsonstring1=json.dumps(jsonstring1)
jsonstring1=json.loads(jsonstring1)
print jsonstring1.keys()
print jsonstring1['results'][0]['policy']

jsonstring2='''{"results":[{"id":"1","name":"\u9ed8\u8ba4\u5206\u7ec4","policy":"4","timer_scan_setting":"{\"last\":\"10.29.13\",\"setting\":\"fulldisk\",\"type\":\"day\",\"hour\":\"13\"}"},
{"id":"2","name":"\u6d4b\u8bd5\u7684","policy":"1","timer_scan_setting":"{\"last\":\"10.29.15\",\"setting\":\"fulldisk\",\"type\":\"day\",\"hour\":\"15\"}"},{"id":"4","name":"\u4ea7\u54c1\u7ec4","policy":"3","timer_scan_setting":"{\"last\":\"10.8.15\",\"setting\":\"disable\"}"}]}'''

json.loads(jsonstring2)