I have been getting:

Error listing Confluence spaces: com.atlassian.confluence.api.service.exceptions.GoneException: This deprecated endpoint has been removed.

while using the library with an OAuth token.

It appeears the confluence.get_all_spaces() method fails with a 401 because OAuth authentication requires using the Atlassian API gateway (https://api.atlassian.com/ex/confluence/{cloud_id}), which has already removed the deprecated /rest/api/space endpoint.