text: import gevent
  import urllib.parse
  
  
  def application(env, start_response):
      start_response("200 OK", [("Content-Type","text/html")])
  
      query_arg = urllib.parse.parse_qs(env["QUERY_STRING"])
      wait_time = float(query_arg.get("duration", (5,))[0])
  
      gevent.sleep(wait_time)
  
      return [b"Waited %d" % wait_time]
  