Paste uses pkg_resources.declare_namespace:

>>> import sys

...

...

import paste paste.__path__

['/usr/local/lib/python2.5/site-packages/Paste-1.6-py2.5.egg/paste', '/usr/local/lib/python2.5/site-packages/PasteDeploy-1.3.1-py2.5.egg/ paste', '/usr/local/lib/python2.5/site-packages/PasteScript-1.6.2- py2.5.egg/paste']

...

...

del sys.modules['paste'] import paste paste.__path__

['/usr/local/lib/python2.5/site-packages/Paste-1.6-py2.5.egg/paste']

Whereas pkgutil.extend_path does the right thing and restores paste.__path__ to contain the 3 paths

-- Philip Jenvey