Edit: This issue should now be resolved.
You should restart your server to ensure you're using the most recent version.
You can do this on Jupyterhub by going to File> Hub Control Panel> Stop My Server > Start My Server.
Please reach out if you're still experiencing issues.
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ADMIN NOTICE: We are aware of the 500: Internal Server Error on the KX Academy projects.
We are working on it and will update the forum and Community Slack channel once we have it resolved.
Thanks for your patience.