Here is the link to the code which is being in-browser remote executed
There is no "explanation" next to or within the file. A exercise14.rst or test_exercise14.py would be nice.
The Explanation link provided contains a mountain of visual shit (aka noise) none of which looks like exercise14.py code.
The OP is trying to teach us, i get that. Looks like i'm failing the (mountain of visual shit) reading comprehension section of this exercise.