Python package status

[Laszlo 'GCS' Boszormenyi <gcs@lsc.hu>]

Dear Mentors,

 I would like to ask advice with Python. I have a package, which depends
on it, and previously I depended on an exact version (2.3) thus altered
the interpreter in each file to be python2.3 instead of generic python.
It worked, but upstream put extra effort into that it should work with
Python 2.0.0 or greater, thus I would like to change my package. As I
see, python1.5 already removed from the archive, but I have the
following questions:
- can it be that python1.5 still lying around on older installations,
  thus /usr/bin/python may point to it?
- would it be good to depend only on python, without versioning, as
  python1.5 is gone, or as the previous question implies python1.5 may
  be around, so I should conflict with it?

The root of my problems is that I don't see newer Python packages to
conflict and replace the old Python, hence my email.

Thanks in advance for any pointers,
Laszlo/GCS