It's a mess.

But it's important.

Distributions

This is what people download

These are what you find on PyPI, e.g. scikit-learn

Modules 

How code is organised

import csv

csv is a module.

Packages

A 'higher level' module.

sklearn is a package.

from sklearn import preprocessing

Scripts

These are the raw source code.

In Python, every script is a module.

So how do you make these?

Scripts are easy!

Just write them. 

Modules are easy!

Modules are just scripts - anything in the global scope of the script is importable.

Packages are easy!

Demo...

Create a module with imports

Create a package which allows exports

Create a distribution