In order to use arcpy you have to have ArcGIS Pro installed and licensed. If you have it installed and licensed, try opening it (and leaving it open) and then running the script.
It seems to go way back to the "import arcpy" line.
ArcMap is installed on your machine properly?
Can you do an "import arcpy" without issue? If you can't then did you check out the professor's html file about how to install the "classtools" module?
In past notebooks, I was able to "import arcpy" just fine. It wasn't until this time that the error occurred... it's very odd. My professor confirmed that I installed the "classtools" module correctly.
Now I just skipped the notebook I was working on (the one giving me the errors) then tried the next Notebook in my assignment list and everything worked. Could the issue be with the notebook I was sent to work on?