… or in other words…
Why is this snippet part of setup.py in all Zope projects?
install_requires = 'setuptools',
This sounds weird at first, but there is good reason.
setuptools provides pkg_resources, and the latter is used in __init__.py, in order to declare a namespace package.
__import__('pkg_resources').declare_namespace(__name__)
Still confused?
While pkg_resources-style namespace packages are no longer recommended for new projects, this approach was used to split large packages, and retrieve the contents from more than one location.
examples from the wider Zope universe
zc.*z3c.*zope.*Products.*five.*grokcore.*
further reading
http://peak.telecommunity.com/DevCenter/setuptools#namespace-packages
thanks
While I stumbled upon namespace packages now and then, and I read about them a bit, it was Jason who connected the dots for me in
https://github.com/zopefoundation/zc.lockfile/issues/22
update
Anthony Sottile pointed out that the import is no longer necessary when dropping Python 2. And this is a good thing, as the import of pkg_resources can add a whopping 300-1000 ms to import time!
https://twitter.com/codewithanthony/status/1286348771048263680
The reason behind: PEP 420 - Implicit Namespace Packages