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.

從 Reading Code 區段和連結的 howdoi/howdoi.py 範例開始。撰寫一份正式說明，解釋 issue 中描述的 Python 2/3 import 處理、控制流程和一致的 API，然後將其新增至適當的頁面。當範例及其教學重點包含在一個 pull request 中時，即視為完成。