This was a deliberate change in Python 3.14 specifically, should be noted that the old code worked on every earlier Python version before this. It also was not documented in the release notes, but it was easy to find people complaining about them tightening the API here. Ref: https://discuss.python.org/t/argparse-valueerror-action-store-true-is-not-valid-for-positional-arguments/106355
==== mach ==== Mach (German for *do*) is a generic command dispatcher for the command line. To use mach, you install the mach core (a Python package), create an executable *driver* script (named whatever you want), and write mach commands. When the *driver* is executed, mach dispatches to the requested command handler automatically. To learn more, read the docs in ``docs/``.