Minimal Python WSGI Hello World

from wsgiref.util import setup_testing_defaults
from wsgiref.simple_server import make_server

def simple_app(environ, start_response):
    start_response("200 OK",[('Content-type', 'text/html')] )
    return ("""<button onclick="window.location='/hello'">say hello</button> """
                if "hello" not in environ["PATH_INFO"] else
            """<h1>Hello World</h1>""")

make_server('', 8080, simple_app).serve_forever()