This is DocFileSuite function source code
(http://svn.python.org/view/python/trunk/Lib/doctest.py) :

::

    def DocFileSuite(*paths, **kw):
        """A unittest suite for one or more doctest files.

        The path to each doctest file is given as a string; the
        interpretation of that string depends on the keyword argument
        "module_relative".

        A number of options may be provided as keyword arguments:

This is DocFileSuite documentation
(http://svn.python.org/view/python/trunk/Doc/library/doctest.rst) :

::

    .. function:: DocFileSuite([module_relative][, package][, setUp][,
tearDown][, globs][, optionflags][, parser][, encoding])

       Convert doctest tests from one or more text files to a
       :class:`unittest.TestSuite`.

       The returned :class:`unittest.TestSuite` is to be run by the
unittest framework
       and runs the interactive examples in each file.  If an example in
any file
       fails, then the synthesized unit test fails, and a
:exc:`failureException`
       exception is raised showing the name of the file containing the
test and a
       (sometimes approximate) line number.

       Pass one or more paths (as strings) to text files to be examined.


I think "paths" argument missing in this documentation.

Regards,
Stephane