I have gone through existing topics , and tried the available cases, they seem to pass.
Base cases generally imply there’s something wrong with the logic itself. I will handout a testcase to you this time. I would suggest trying to understand that and writing your own method / adding logic to the existing “test_” methods that the approach pack takes you through to cover the missing piece of logic. DMd you on Slack.
Closing this topic as your issue is resolved by the mentor. If it is still not resolved, Kindly un-mark the accepted solution or create a new topic and post this question as a reference link in the description of the new topic.