Addition of specific example of great code from one of the listed repositories.

I absolutely love the Reading Code section, and I've been going through some of the repositories and identifying specific examples of why the code is good.

I was hoping to add one such example to the page. Specifically, from howdoi. It's virtually at the top of the codebase and it deals with standardizing the repository for Python 2 and 3.

https://github.com/gleitz/howdoi/blob/master/howdoi/howdoi.py

# Handle imports for Python 2 and 3
if sys.version < '3':
    import codecs
    from urllib import quote as url_quote
    from urllib import getproxies

    # Handling Unicode: http://stackoverflow.com/a/6633040/305414
    def u(x):
        return codecs.unicode_escape_decode(x)[0]
else:
    from urllib.request import getproxies
    from urllib.parse import quote as url_quote

    def u(x):
        return x

I think that there are two (and a half) key pedagogical takeaways from this.

The half takeaway is that supporting different versions of Python need not be a grueling task.

The remaining two are -

1. Appropriate use of control flow for module imports and function creation
2. Standardizing an API so that its source is indistinguishable to the rest of the code and functionality is consistent.

I haven't formally written this up yet, but if you think it would be a useful example, I can do that and submit a pull request.

Comienza con la sección Reading Code y el ejemplo vinculado howdoi/howdoi.py. Redacta una explicación formal del manejo de imports de Python 2/3, el flujo de control y la API coherente descritos en el issue, y añádela a la página correspondiente. Se considerará completado cuando el ejemplo y sus conclusiones pedagógicas estén incluidos en un pull request.