Hello, @tbarna22,
Welcome to this community!
Judging from your screenshot, I think it was because a code cell was removed. If you look at my screenshot below, there should be a code cell starting with #Load data before the cell in your screenshot.
This code cell is responsible for defining Y. If it is missing from your notebook, please follow these instructions to get a new notebook, noting that during which you will have to rename your current notebook before the system can get you a new one, and then you can copy your work from the renamed notebook.
Cheers,
Raymond
PS: We are not supposed to share assignment notebook here since it is a violation of the use of this forum, but don’t worry about it because I will remove it for you. Please only share screenshots of the full error here if you want to discuss any error.