mod_python seems to be missing a file

[MM]

I've followed the mod_python documentation to the letter.  It seems to be on
the verge of working with the one following problem:

from mod_python import apache

this is the first line of the test program you're told to write to see if
you're up and running.  The problem with this is that the apache.py file in
the mod_python package is trying to import a file called _apache.  I cannot
find this file anywhere and, apparently, neither can Python, since it
complains about it, as well.  Any help on where this file can be found would
be appreciated.