Namespace packages let you ship `foo.bar` and `foo.baz` separately. `bar` and `baz` are really two separate packages that are both part of the `foo` namespace.

Namespace packages let you ship `foo.bar` and `foo.baz` separately. `bar` and `baz` are really two separate packages that are both part of the `foo` namespace. `foo` is not a real package. They are not new but implicit namespace packages are new-ish. Before 3.3 it was more complicated to set up, now you just omit __init__.py from `foo`. I don't see any reason to use this if `foo` is shipped as a single package.