Hullo,

It looks like the python39 package is missing dependencies on
python-setuptools-wheel and python-pip-wheel.  I've not checked, but I
suspect earlier Python versions are missing the same dependencies.
Without these, the Python built-in venv module doesn't work:

    $ python3 -m venv v
    Error: Command '['/home/WDAGUtilityAccount/v/bin/python3', '-Im', 'ensurepip', '--upgrade', '--default-pip']' returned non-zero exit status 1.

Compare when the both python-setuptools-wheel and python-pip-wheel are
installed:

    $ python3 -m venv v
    $ . v/bin/activate
    (v) $ python3 -c 'import sys; print(sys.path)'
    ['', '/usr/lib/python39.zip', '/usr/lib/python3.9', '/usr/lib/python3.9/lib-dynload', '/home/WDAGUtilityAccount/v/lib/python3.9/site-packages']
    (v) $ deactivate

I've attached cygcheck files from sandbox VMs for both the broken and
working cases.  I'm not sure what the correct fix is here -- possibly
adding dependencies, possibly changing how things are packaged -- but
I'd expect Python standard library modules to either work or to give an
error message that makes it clearer what additional packages are
required to make them work.

Cheers,

Adam