I can’t say these will “advance your Python skills”, but these are definitely projects that are worth a look:

- Django

- Django-Nap

- Django REST framework

- Flask

- Twisted

- Tornado

- Klein

- NumPy

- SciPy

- Pandas

Are they the cleanest, most beautiful codebases? Maybe not. But they tackle some interesting problems, some of them with some overlapping so you may get to see different ways/philosophies of solving the same problem, even though the Zen says there should be only one obvious way.

Django is a batteries-included web app framework. Flask is minimal. Tornado does async networking. Klein is like Twisted and Flask had a child (because a Klein bottle is a twisted flask). NumPy and SciPy deal with matrices and massive number crunching, leveraging Cython. Pandas deals with tabular, sometimes sparse data frames (if I remember correctly).

lmao :')