Raymond Hettinger wrote:
> Similarly, make sure that clarity and cut-and-pastability don't get lost by adding ... PS2 prompts that uglify the examples.

Note that Sphinx adds a ">>>" button to the upper right of the example
that, when clicked, makes all of the prompts and output disappear so
that the code (and only the code) can be copied easily.  Not having
the ps2 prompts breaks that button.