[Distutils] setuptools: why does it install ctypes twice?

[Victor Stinner]

Hi,

I'm one of the authors of pynetfilter_conntrack:
http://cheeseshop.python.org/pypi/pynetfilter_conntrack
http://software.inl.fr/trac/trac.cgi/wiki/pynetfilter_conntrack

Here is the setup.py:
http://software.inl.fr/trac/trac.cgi/browser/mirror/edenwall/pynetfilter_conntrack/trunk/setup.py

My problem is that "sudo ./setup.py install" reinstall ctypes 1.0.1 and 
ElementTree 1.2.6 whereas they are already installed by Ubuntu (using 
apt-...).

Should I use different install_requires option? Current one is:
  install_requires = ("ctypes>=0.9.6", "IPy>=0.42", "ElementTree>=1.0")

Bye, Victor Stinner
PS: Please CC-me to your answers ;-)
-- 
Victor Stinner
http://www.inl.fr/