A Python module is simply a Python source file, which can expose classes, functions and global variables.
When imported from another Python source file, the file name is treated as a namespace.
A Python package is simply a directory of Python module(s).
For example, imagine the following directory tree in /usr/lib/python/site-packages
directory:
mypackage/__init__.py <-- this is what tells Python to treat this directory as a package
mypackage/mymodule.py
So then you would do:
import mypackage.mymodule
or
from mypackage.mymodule import myclass