pydo optionally works along with virtualenv-multiver to help run a

command across a range of Python versions. This is useful for installing

dependencies, setting up development environments, or performing various

tests on multiple Python versions with one command.
pydo accepts a list of Python versions, which may include ranges

(e.g., 3.7-3.11). It looks for versioned scripts (like pip3.8 or

easy_install-2.7) to run, and also handles running pip using

pythonX.Y -m pip syntax to avoid issues with Python's pip scripts in

multi-versioned environments.
If versions aren't provided on the command line, pydo will look for

versions recorded in $VIRTUAL_ENV/.pydorc. This is created when

generating a new multi-version environment.
If that's not present, versions are loaded from any .pydorc,

pyproject.toml, or setup.cfg found in the current directory up to

the root.
Some of the functionality will soon be used in virtualenv-multiver to

ease environment creation.

Been using this for environments for quite a while.
Tested with the various configuration files at different levels in the

tree.
Tested with and without ranges and duplicate specified versions.