optparse.py: FutureWarning error

[kosuke]

I keep getting the following error/warning message when using the
python based program getmail4:

/usr/lib/python2.3/optparse.py:668: FutureWarning: %u/%o/%x/%X of
negative int will return a signed string in Python 2.4 and up
  return ("<%s at 0x%x: %r>"

I'm using python2.3.5 on a debian sid box.

The getmail4 website/FAQ maintains that this is a bug in the optparse
module.

Any idea on how to resolve this?

Thanks
Kevin