Simple Python script as SMTP server for outgoing e-mails?

[Gilles]

Hello

	Every once in a while, my ISP's SMTP server refuses to send
perfectly legit e-mails because it considers them as SPAM.

So I'd like to install a dead-simple SMTP server on my XP computer
just to act as SMTP backup server.
All I'd need is to change the SMTP address in my e-mail client, and
off they go. No need for anything else like user authentication or
SPAM control.

Is there a no-brainer, ready-to-use solution in Python that I could
use for this?

Thank you.