[tariq@localhost6 tariq-twisted-trunk]$ trial twisted
Traceback (most recent call last):
  File "/usr/local/bin/trial", line 4, in ?
    import pkg_resources
  File "/usr/lib/python2.4/site-packages/pkg_resources.py", line 2479, in ?
    working_set.require(__requires__)
  File "/usr/lib/python2.4/site-packages/pkg_resources.py", line 585, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python2.4/site-packages/pkg_resources.py", line 483, in resolve
    raise DistributionNotFound(req)  # XXX put more info here
pkg_resources.DistributionNotFound: Twisted==13.0.0-r38288