The lab was designed to run on the Cousera environment that has the correct sklearn package version to run the code successfully. You were experiencing that error probably because you are running it in a different environment. 'none' was a valid option in older sklearn.
Please run the lab on Cousera, or you can change it yourself from 'none' to None to make it pass. The error message should have shown you where the problematic line was, and in which script file it is.