(Converting this issue into Derby entry #7.  Serhiy has stated that
he is abandoning his ElementTree patch; it may make a good starting point for you if you take over this issue.)

This issue is part of the Great Argument Clinic Conversion Derby,
where we're trying to convert as much of Python 3.4 to use
Argument Clinic as we can before Release Candidate 1 on January 19.

This issue asks you to change the following bundle of files:
    Modules/_elementtree.c: 31 sites
    PC/_msi.c: 15 sites
    PC/bdist_wininst/install.c: 5 sites

Talk to me (larry) if you only want to attack part of a bundle.

For instructions on how to convert a function to work with Argument
Clinic, read the "howto":
    http://docs.python.org/dev/howto/clinic.html