[doc] The demo of 'tls_auth_handler' is not work

[karezachen]

ENV

tls_auth_handler_demo.py --> code form README.md

from prometheus_client import CollectorRegistry, Gauge, push_to_gateway
from prometheus_client.exposition import tls_handler
def my_auth_handler(url, method, timeout, headers, data):
    certfile = 'client-crt.pem'
    keyfile = 'client-key.pem'
    return tls_auth_handler(url, method, timeout, headers, data, certfile, keyfile)
registry = CollectorRegistry()
g = Gauge('job_last_success_unixtime', 'Last time a batch job successfully finished', registry=registry)
g.set_to_current_time()
push_to_gateway('localhost:9091', job='batchA', registry=registry, handler=my_auth_handler)

python tls_auth_handle_demo.py

LOG

Traceback (most recent call last):
  File "/private/tmp/tls_auth_handler_demo.py", line 2, in <module>
    from prometheus_client.exposition import tls_handler
ImportError: cannot import name 'tls_handler' from 'prometheus_client.exposition' (/private/tmp/venv/lib/python3.9/site-packages/prometheus_client/exposition.py)

SHOULD BE

client_python/README.md

Line 490 in 4ab083e

from prometheus_client.exposition import tls_handler

update to

from prometheus_client.exposition import tls_auth_handler

[csmarchbanks]

Good catch, would you like to open a PR to fix this?

[karezachen]

Yes, please check it.

[csmarchbanks]

Fixed in #876