python setup.py question

Question

So I have a folder structure something like this:

pckA - core
     - io
pckB - core
     - io
     - main

Now I have to create a setup.py file for both there packages. My current approach is :

from distutils.core import setup
import setuptools

setup(
    name='ProjectExternals',
    version='0.1dev',
    packages=["pckA","pckA.core","pckA.io","pckB","pckB.core","pckB.io","pckB.main"],
    license='Not decided yet',
    author='',
    author_email='',
    long_description="",
    install_requires=["numpy","quantities"]
)

This setup.py is located in the same folder as pckA and pckB .So my question is : is it necessary to add all the subpackages like pckA.core etc or does setuptools know to install these as well?