I am trying to stop an instance using openstack api with the help of python.

from openstack import connection
import os

def auth_args():
    d = {}
    d['username'] = os.environ['OS_USERNAME']
    d['password'] = os.environ['OS_PASSWORD']
    d['auth_url'] = os.environ['OS_AUTH_URL']
    d['project_name'] = os.environ['OS_TENANT_NAME']
    d['project_domain_id'] = os.environ['OS_PROJECT_DOMAIN_ID']
    d['user_domain_id'] = os.environ['OS_PROJECT_DOMAIN_ID']
    return d

conn=connection.Connection(**auth_args())
for server in conn.compute.servers():
  if server.name == 'server_test':
    server.stop(server.id)

i have set a source file then i am trying to run this code, but it gives the below error.

Traceback (most recent call last):

  File "stop_opsk_srv.py", line 20, in <module>
    server.stop(server.id)
  File "/root/.local/lib/python2.7/site-packages/openstack/compute/v2/server.py", line 345, in stop
    self._action(session, body)
  File "/root/.local/lib/python2.7/site-packages/openstack/compute/v2/server.py", line 181, in _action
    return session.post(

I am able to retrieve instance details and meta data using the same conn.compute.servers() method. Please help.