Storing Python procedures in XML

[slaytanic killer]

Hi,

I hope this isn't a basic question, but I notice a tactic people seem
to use is storing Python code in XML, like event-handlers, for more
fluid representation than sticking them in .py files.  What is this
practice called, and where can I go to find out more about it or
download libraries which facilitate this?

FYI, I found this in Jext, which is a Java text editor which uses
Jython libraries.  Java touts dynamic programming, but not quite as
dynamic as this.

Thanks for any help.