[Python 2.7.3] What's the difference between these two uses of "for"?

[Yves S. Garret]

N00b question.  But here is the code:

http://bin.cakephp.org/view/709201806

In the first example, the first for-loop is run and then the list is assigned to the tricky variable.  But, what 
happens in the second example?  Does the loop after "in" get run only once or multiple number of times?