figure - shows one that gives the python exception and details as part of the reply after python-raised exception is caughtas usualthe exception details are fetched from sys exc_infoand python' traceback module is used to generate stack trace passing state information in url link parameters the central mechanism at work in example - is the generation of urls that embed message numbers and mail account information clicking on any of the view links in the selection list triggers another scriptwhich uses information in the link' url parameters to fetch and display the selected email as mentioned in because the list' links are programmed to "knowhow to load particular messagethey effectively remember what to do next figure - shows part of the html generated by this script (use your web browser view source option to see this for yourself-- did save as and then opened the result which invoked internet explorer' source viewer on my laptopdid you get all the details in figure - you may not be able to read generated html like thisbut your browser can for the sake of readers afflicted with human-parsing the pymailcgi server