问题
I have once seen a Python package with one flat src/ folder containing setup.py, but which still declare itself as namespace or namespace.foo package and you can import files from the package as from namespace.foo import x.
This was done with some setup.py option and tricks. However, I have unable to find the source or the package how this was done and I am now looking for examples for it.
来源：https://stackoverflow.com/questions/9587667/folderless-namespaced-packages-with-setuptools