[mod_python] mptest.py test

After installed mod_python (apache 2.0.54, python
2.3.5,mod_python-3.1.3.win32-py2.3.exe),
Instead "Hello World!", IE displays the whole code for the url
http://localost/mptest.py:
from mod_python import apache

def hello(req):
    req.write("Hello World!")
    return apache.OKI tried other version of apache with corresponding
mod_python, no differences.Please help. Thanks