gistfile1.py

from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app

class MainPage(webapp.RequestHandler):
  def get(self):
    self.response.headers['Content-Type'] = 'text/plain'
    self.response.out.write('Hello, webapp World!')

application = webapp.WSGIApplication([('/', MainPage)],
                                     debug=True)

def main():
  run_wsgi_app(application)

if __name__ == "__main__":
  main()