With a item.addClaim(claim):
WARNING: API warning (wbcreateclaim) of unknown format: {'messages': [{'name': 'wikibase-conflict-patched', 'parameters': [], 'html': {'*': 'Votre modification a été intégrée dans la dernière version.'}, 'type': 'warning'}]}
Translation in English: Your change has been incorporated in the latest version. That corresponds to an edit conflict that was merged by the server.
It looks like this wikibase-conflict-patched error is not handled by pwb ?
Is the display of this warning wanted? necessary?