Devs unknowingly use “malicious” modules snuck into official Python repository Code packages available in PyPI contained modified installation scripts.

Cython generates the second kind of module: C libraries that talk to Python’s internals, and that can be bundled with existing Python code. Cython code looks a lot like Python code, by design.

Python virtual environments shine for keeping projects and conflicting packages separate. Just keep these dos and don’ts in mind.