[mod_python] Package notation in PythonHandler directive

Continuing to explore mod_python, I'm having trouble with package
notation in the PythonHandler directive.

I'm looking at the mod_python docs, and the Tutorial section 3.2 in
particular. It suggests that you could have a directory structure as
follows:

<your base dir>
  |
  +- .htaccess (file)
  +- subdir (directory)
      |
      +- myscript.py (file)

The .htaccess file would look as follows:

    AddHandler python-program .py
    PythonHandler subdir.myscript
    
and the myscript.py file in the 'subdir' subdirectory would look as
follows:

    from mod_python import apache
    
    def handler(req):
        req.content_type = "text/plain"
        req.send_http_header()
        req.write("Hello, World!")
    
        return apache.OK

If I do this, I get a 500 Internal Server Error and the following
appears in the apache logs:

    [Mon Aug 19 12:12:57 2002] [error] PythonHandler subdir.myscript:
    Traceback (most recent call last):
    [Mon Aug 19 12:12:57 2002] [error] PythonHandler subdir.myscript:  
    File "/usr/lib/python2.1/site-packages/mod_python/apache.py", line
    181, in Dispatch
        module = import_module(module_name, _req)
    [Mon Aug 19 12:12:57 2002] [error] PythonHandler subdir.myscript:  
    File "/usr/lib/python2.1/site-packages/mod_python/apache.py", line
    332, in import_module
        f, p, d = imp.find_module(parts[i], path)
    [Mon Aug 19 12:12:57 2002] [error] PythonHandler subdir.myscript:
    ImportError: No module named subdir
    
What am I doing wrong?

Cheers,
Fabian