title: Tornado: get request arguments
body: <p>I have following code:</p>
  
  <pre><code>application = tornado.web.Application([
      (r"/get(.*)", GetHandler),
  ])
  
  class GetHandler(tornado.web.RequestHandler):
      def get(self, key):
          response = {'key': key}
          self.write(response)
  </code></pre>
  
  <p>when I go to <code>localhost:port/get?key=python</code> I receive empty key value <code>{'key': ''}</code>. What is wrong here?  </p>