The web.error module provides enhanced functionality similar to the cgitb module distributed with Python. If an exception is raised the web.error module can catch the error and produce a customised display of the error, the surrounding code and the values of variables in the line which caused the error. It also provides the ability or log errors to a file in various formats.
Using the module you can also provide your own error handling. The example at the end shows you how to create a custom error handler to email error reports to a devloper.