The point is that you need more than just the notebook if you want to run the code in a different environment. Why not just use the course website?
If you want to run it elsewhere you need to download all the files associated with the assignments. There are no official instructions for how to run under spyder or PyCharm or VSCode or Google Colab or name your favorite environment, but there is a topic on the DLS FAQ Thread about how to download all the files.
The functions are there in the assignment in a file called init_utils.py. You just need to download it. There is also a topic on the FAQ Thread about how to find the utility files if you just want to look at them as well.