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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _extract_auth_config(self):
 """Obtains the authentication configurations."""


        service = self._service
        if not service.authentication:
            return {}

        auth_infos = {}
        for auth_rule in service.authentication.rules:
            selector = auth_rule.selector
            provider_ids_to_audiences = {}
            for requirement in auth_rule.requirements:
                provider_id = requirement.providerId
                if provider_id and requirement.audiences:
                    audiences = requirement.audiences.split(u",")
                    provider_ids_to_audiences[provider_id] = audiences
            auth_infos[selector] = AuthInfo(provider_ids_to_audiences)
        return auth_infos