why does "python --version" write to standard error?

[Cameron Simpson]

This seems to write the python version to standard error. That seems
very wrong. And at variance with the manual entry.

Commentry?
-- 
Cameron Simpson <cs at zip.com.au>

This is not a bug. It's just the way it works, and makes perfect sense.
        - Tom Christiansen <tchrist at jhereg.perl.com>
I like that line. I hope my boss falls for it.
        - Chaim Frenkel <chaimf at cris.com>