The PO file format is part of the gettext internationalization and localization system commonly used in Unix-like systems. This system includes tools to ease the translation work.
This recipe demonstrates how to use these tools to help translate our addon modules. We want to use it on a custom module, so my_module created in Chapter 4, Creating Odoo Addon Modules, is a good candidate. However, feel free to replace it with some other custom module you have at hand, replacing the recipe's my_module references as appropriate.