python3处理json数据

[root@mongo_rs1 tmp]# cat test.py 
import requests
import json

url = 'https://wxtest.mayocase.com:8888/actuator/metrics/tomcat.sessions.active.max'
payload = {'some': 'data'}
headers = {'content-type': 'application/json'}
ret = requests.get(url, data=json.dumps(payload), headers=headers)
print(ret.text)
json_data=json.loads(ret.text)

value=json_data.get('measurements')[0].get('value')
measurements=json_data.get('measurements')
#strs=measurements[0]
#value=strs.get('value')

print(value)
print(value-1.0)

#print(ret.cookies)
[root@mongo_rs1 tmp]# 
[root@mongo_rs1 tmp]# python3 test.py 
{"name":"tomcat.sessions.active.max","measurements":[{"statistic":"VALUE","value":1.0}],"availableTags":[]}
1.0
0.0
[root@mongo_rs1 tmp]# cat t