[python] How to import classes defined in __init__.py

I am trying to organize some modules for my own use. I have something like this:

lib/
  __init__.py
  settings.py
  foo/
    __init__.py
    someobject.py
  bar/
    __init__.py
    somethingelse.py

In lib/__init__.py, I want to define some classes to be used if I import lib. However, I can't seem to figure it out without separating the classes into files, and import them in__init__.py.

Rather than say:

    lib/
      __init__.py
      settings.py
      helperclass.py
      foo/
        __init__.py
        someobject.py
      bar/
        __init__.py
        somethingelse.py

from lib.settings import Values
from lib.helperclass import Helper

I want something like this:

    lib/
      __init__.py  #Helper defined in this file
      settings.py
      foo/
        __init__.py
        someobject.py
      bar/
        __init__.py
        somethingelse.py

from lib.settings import Values
from lib import Helper

Is it possible, or do I have to separate the class into another file?

EDIT

OK, if I import lib from another script, I can access the Helper class. How can I access the Helper class from settings.py?

The example here describes Intra-Package References. I quote "submodules often need to refer to each other". In my case, the lib.settings.py needs the Helper and lib.foo.someobject need access to Helper, so where should I define the Helper class?

You just put them in __init__.py.

So with test/classes.py being:

class A(object): pass
class B(object): pass

... and test/__init__.py being:

from classes import *

class Helper(object): pass

You can import test and have access to A, B and Helper

>>> import test
>>> test.A
<class 'test.classes.A'>
>>> test.B
<class 'test.classes.B'>
>>> test.Helper
<class 'test.Helper'>

Add something like this to lib/__init__.py

from .helperclass import Helper

now you can import it directly:

from lib import Helper

If lib/__init__.py defines the Helper class then in settings.py you can use:

from . import Helper

This works because . is the current directory, and acts as a synonym for the lib package from the point of view of the settings module. Note that it is not necessary to export Helper via __all__.

(Confirmed with python 2.7.10, running on Windows.)

Edit, since i misunderstood the question:

Just put the Helper class in __init__.py. Thats perfectly pythonic. It just feels strange coming from languages like Java.

Yes, it is possible. You might also want to define __all__ in __init__.py files. It's a list of modules that will be imported when you do

from lib import *

Maybe this could work:

import __init__ as lib