You could write a specification in your favorite word processor, but ideally the specification is a part of your code; it will need to be kept with the code and synchronized with any changes to the application. For that reason, we're going to write it in our text editor using the reStructuredText markup language.
For Python documentation, reStructuredText, or reST, is the official markup language. The Python community encourages the use of reST to document Python projects, and many packaging and publication tools used in the Python community expect the reST format. We'll cover reST in more depth in Chapter 5, Planning for the Expansion of Our Application, but you can find the official documentation ...
