[python-win32] killing overlay extensions

[TK Soh]

I'd like to know what's the 'proper' way to stop a pythonwin's overlay
shell extension from kicking in. I've not been able find much
documentation on this, particularly the return values of
GetOverlayInfo() function. Based on sample that I've found, the
GetOverlayInfo() function returns a tuple of (icon_path, 0,
shellcon.ISIOI_ICONFILE), and it's not clear to me what the '0' is
representing.

So far my way to 'kill' the extension is either to raise an exception
in, or return None from, GetOverlayInfo(). Though it seemed to work
fine so far, I am not sure if this will create and ill effect down the
road.  I'd really appreciate if anyone can share some experience on
this. Thanks.