six

six is a Python 2 and 3 compatibility library that provides utility functions for smoothing over differences between the two Python versions, enabling codebases to run on both without modification. It consists of a single Python file (six.py) covering string types, integer types, standard library moves, metaclass helpers, and more. Current version is 1.17.0, released December 2024. The project is in maintenance mode: Python 2 reached end-of-life in 2020, and in 2024 it is entirely normal for projects to support only Python 3, so new code should not take a dependency on six — it is primarily relevant for maintaining legacy dual-version codebases or as a transitive dependency.