Querying Wikidata

Hello,

Is there a good mean to query the sparql wdqs service of wikidata?
I've tried some python code to do it, with relative success.
Success, because some requests gives the expected result.
Relative, because the same query sometimes gives an empty response either
from my code or directly in the WDQS interface, where it's possible to see
that a sparql query sometimes gives an empty response, sometimes the
expected reponse without message or status to know that the response is
erroneous.
(demo is difficult, because it seems to depend of the load of the wdqs
service)
I've found the following info:
*
https://www.mediawiki.org/wiki/Wikidata_Query_Service/User_Manual#Query_limits,
which suggest a possible error HTTP code 429, which I never receive
* https://phabricator.wikimedia.org/T179879, which suggest a possible
connexion with OAuth, but such possibility is never documented in the
official documentation

None of them gives a practical method to get a response and trust it.

Have you some advices?
(comment: this question is relative to the post
https://onsem.wp.imt.fr/2019/01/06/paris-musees-and-wikidata-establishing-links/
)


--
Jean-Claude Moissinac