[Distutils] namespace packages ok to contain code?

Where I work we're considering a change to moving a group of packages to using namespaces. We want the namespace paths to reflect a dependency hierarchy, and the current plan requires putting some source code into actual module distributions at the level of some of the namespace packages. Example: toplevel.midlevel toplevel.midlevel.a toplevel.midlevel.b Each of these three is a separate module distribution We want to put core library code in the midlevel. Some have warned this is not usually done, but no specific problems with this approach have been identified. Any guidance on this would be appreciated. Thanks!