def simple_app(environ, start_response):
    """Simplest possible application object""" 
    status = '200 OK'
    response_headers = [('Content-type','text/plain')]
    start_response(status, response_headers)
    return ['My Own Hello World!\n']

class SimpleApp:
    """Produce the same output, but using a class
    """
    def __init__(self, environ, start_response):
        self.environ = environ
        self.start = start_response

    def __iter__(self):
        status = '200 OK'
        response_headers = [('Content-type','text/plain')]
        self.start(status, response_headers)
        yield 'My Own Hello world!\n'

if __name__ == '__main__': 
    from wsgiref.simple_server import make_server, demo_app

    # httpd = make_server('', 8000, simple_app)
    # the same but using a class
    httpd = make_server('', 8000, SimpleApp)
    
    print "Serving HTTP on port 8000..."

    # Respond to requests until process is killed
    httpd.serve_forever()