https://github.com/mircealex/solutions/blob/master/Mission529Solutions.ipynb
Above link emits a 404 error. Could you kindly fix?
I am not sure where you got that link from, but this is the official solution link - solutions/Mission529Solutions.ipynb at master · dataquestio/solutions · GitHub
You can get Solution Links by clicking on the Key icon (next to the Download button) on top of the Jupyter Notebook in the classroom.