Teething troubles with Python on a Mac

[Avi]

> Apart from the initial installation of Python itself, I
> never use an installer to install a Python package if I
> can avoid it. I wouldn't trust it to install into the right
> Python version.

On that: how would I go about updating the system Python, then?  Or is
that going to be stuck at whatever it is, and Mac users are expected
to run two simultaneous Python installations?  I'm not entirely
comfortable with having a separate MacPython (I used to do so, but it
caused so many issues with installing new packages that I gave up on
it) and would prefer to just update system Python.

- Avi