Add illustration for code organization

Author: gjbex

source-code/README.md

@@ -25,7 +25,9 @@ was used to develop it.
 1. `testing`: illustrates writing unit tests with `unittest` and
    `pytest`.
 1. `oo_vs_functional.ipynb`: comparing object-oriented approach to
-  functional approach, including coroutines.
+   functional approach, including coroutines.
 1. `metaclasses`: illustration of the use of metaclasses in Python.
 1. `data-structures`: illustration of Python and standard library data
    structures.
+1. `code-organization`: illustration of how to organize code in packages
+   and modules.

source-code/code-organization/README.md

@@ -0,0 +1,12 @@
+# Code organization
+
+Simple example of code organization in packages, modules.
+
+## What is it?
+
+1. `my_pkg`: Python package.
+  1. `__init__.py`: package-level documentation and version
+     information.
+  1. `my_module.py`: simple module in the `my_pkg` package.
+1. `my_script.py`: Python script that uses the `my_module`
+  module in the `my_pkg` package.

source-code/code-organization/my_pkg/__init__.py

@@ -0,0 +1,5 @@
+'''
+This is the my_pkg documentation
+'''
+
+__version__ = '1.0'

source-code/code-organization/my_pkg/my_module.py

@@ -0,0 +1,2 @@
+def hello(name):
+    return f'hello {name}'

source-code/code-organization/my_script.py

@@ -0,0 +1,5 @@
+#!/usr/bin/env python
+
+import my_pkg.my_module
+
+print(my_pkg.my_module.hello('world'))