Python still remembers script after change and save

[Paul Brian]

All,

I am (fairly) sure I have read this before, but cannot find the posts again.

I occasionally come across a situation where I have changed a file, rerun
the file in python but python still produces an error, quoting the original
file in the error string

Eventually the only workaround is to shutdown and restart the IDE or python
(PythonWin usually for me)

Does anyone

a) Have an explanation for this (still hazy on the internals of python)
b) Have a good workaround

on b) I seem to remeber someone suggesting deleting references to everything
in __main__.__dict__ that did not begin with __
however that seems kludgy or even dangerous.

Thanks in advance....

Paul Brian