A module is a file containing Python definitions and statements. The file name is the module name with the suffix .py
create hello.py then write the following function:
def helloworld():
print "hello"
>>> import hello
>>> hello.helloworld()
'hello'
>>>
To group many .py files put them in a folder. Any folder with an __init__.py is considered a module by python and you can call them a package
|-HelloModule
|_ __init__.py
|_ hellomodule.py
You can go about with the import statement on your module the usual way.
For more information: