PEP 238 states:

     - The standard library will use the future
division statement and
       the // operator when appropriate, so as to
completely avoid
       classic division.

  While the demos/ directory is not technically part of
the standard library, it does contain code that should
work, and that newbies may examine in the course of
learning Python.  Python source there should follow the
same rules as anyplace else.

  I'll volunteer to make the changes and submit a
patch, if it is agreed that the changes should indeed
be made.