You can change the python path that mod_python uses. This is useful if you installed PSE someplace other than the default location.
To change the python path, use the
PythonPath "sys.path + [ '/path/to/PSE-X.X.X' ]"
The part between the quotes is actual python code. In this case, it
says to append the list
['/path/to/PSE-X.X.X'] to the list
sys.path. This tells python to search in /path/to/PSE-X.X.X
for more python libraries.
You can use this directive to set different python paths for each PSE instance (see section 3.1.5).