There might be a problem with

What if the Python version will consist of more than 3 characters?

I originally posted this as a question on Stack Overflow https://stackoverflow.com/questions/48119291/whats-with-the-definition-of-environment-marker-variable-python-version-in-pe Just as Martijn Pieters wrote there, something like ".".join(platform.python_version_tuple()[:2]) would fix the problem.

I also posted about this at pypa/packaging#119