Python's famous libraries
What do Python's most important libraries have in common?
"Important" depends on what you're doing, of course. If you're a data scientist, Pandas is important. For a web developer, Django and Flask matter more.
But I have my own short list of libraries demonstrating some great things you can do with Python. These include Django, Flask, Pandas, SQLAlchemy, Twisted, and Pytest.
I'm sure you can think of others.
It's interesting to look at their code... how these libraries are implemented. And see what uncommon features of the Python language they use:
Advanced function abstractions. Fully exploiting the fact that in Python, functions are first-class objects. Calling abstractions. More generic, flexible function signatures.
Magic methods. Special ways your classes can hook directly into the semantics of Python itself.
Decorators. A powerful, strange metaprogramming tool, that oddly enough, almost all the libs above use in some important way.
When you learn to write Python code leveraging these more advanced constructs, it benefits you in two ways.
The first is obvious: you can do kewl stuff.
You can create the kinds of interfaces these famous libraries use. Your code can more easily do the kinds of things they do.
The second is more subtle. When you learn to write code leveraging these advanced features...
Your fluency of the Python language itself? It EXPLODES. Because each of these features requires you understand Python at a deeper level, before you can use them effectively.
Like you're starting to see into the "matrix" of Python. A different level of mastery.