Unloading COM objects?

[Robert]

Hi,
 I've been fooling around with ATL and making COM automation objects to be
scripted by python. However, each time I rebuild the COM dll, I have to quit
python
because the file is being used (after a win32com.client.Dispatch call). Is
there
any way of unloading the COM object in python? I tried
o=win32com.client.Dispatch("test.object"),
o=None, with no success.

Thanks
Robert