[Distutils] empty namespace package

[Václav Šmilauer]

Hello,

I would like to declare empty namespace package "A.B" inside the 
setup.py of "A", but I am getting

     error in A setup command: Distribution contains no modules or 
package for namespace package "A.B".

The reason for declaring empty namespace package is that I could always 
do "import A.B" from A, knowing that the import will never fail. The 
current situation is that depending on whether some A.B.* is installed, 
import A.B succeeds or fails with ImportError, so I have a few places with

    try: import A.B
    except ImportError: pass # no A.B.* installed

I can live with that, though if there is some option to allow empty 
namespace package, I would be glad to hear about it.

I am using setuptools 0.6.28.

Cheers, Vaclav