[mod_python] What is a directory?

This may sound like a stupid question (and perhaps it is), but I'm asking
it in the context of the PythonInterpPerDirectory directive and a custom
mod_python handler.

If my understanding is correct, it is my handlers job to process the
req argument and produce whatever content it sees fit.  Where I get
that content from, how it is generated, is entirely upto my handler.
I could, for example have my hander generate all pages directly and
never acess the file system at all.

But, before any of this happens, mod_python needs to select or create
an interpreter on which to run my handler.  Presumably, it does this without
actually accessing the target URI, since the target URI might be neither
a file nor a directory (as in the example above).

So my question is, what (in the context of the PythonInterpPerDirectory
directive) is a directory?  I'm guessing it is based on the syntax of the
requested URI.  If I've missed this in the documentaion, somewhere please
tell me where to go...

	Stefan