I'm receiving the following error on challenge #6 of the Lightning Superbadge:

Challenge Not yet complete... here's what's wrong: 
There was an unexpected error in your org which is preventing this assessment check from completing: System.DmlException: Delete failed. First exception on row 0 with id 0035000002hUBgRAAW; first error: DELETE_FAILED, Your attempt to delete Sam the ninja could not be completed because it is associated with the following adventure packages.: null, null : []

Looking at the Developer Console, it looks like the code which checks the system is forgetting to delete the Adventure Package records before deleting the Contact. Has anyone else run into this issue?

Thank you!