Explanation of this Python language feature? [x for x in x for x in x] (to flatten a nested list)

[Walter Hurry]

Steven D'Aprano wrote:

> On Sun, 30 Mar 2014 00:32:58 -0700, Larry Hudson wrote:
>
>> Unfortunately, there is no good word for "USA-ian".  "United States
>> Citizen" is too long and awkward and "United Statesian" is ridiculous. 
>> The common usage of "American" for this is at best ambiguous, and
>> definitely inaccurate (as well as chauvinistic, and rather insulting to
>> other North and South Americans outside the US).
>
> Among fans of the British writer Terry Pratchett, the usual term is 
> Merkins. Including among Merkin fans.
>
Tom Sharpe was there first, I think.
By the way, his books are hilarious.