The Original Aproach.py

import tornado.httpclient
import tornado.ioloop

def handle_response(to_write, response):
    if response.error:
        print "Error: ", response.error
    else:
        to_write = response.body

google_write = ""
yahoo_write = ""

http_client = tornado.httpclient.AsyncHTTPClient();
http_client.fetch("http://google.com",lambda response: handle_response(google_write,response));
http_client.fetch("http://yahoo.com",lambda response: handle_response(yahoo_write,response));

ioloop.IOLoop.instance().start();

The Real Aproach.py

# -*- coding: utf-8 -*-
import tornado.httpclient
import tornado.ioloop

url_list, url_body = ["http://www.google.com","http://www.yahoo.com"], {}
http_client = tornado.httpclient.AsyncHTTPClient();

def all_call_completes(): print(url_body)

if len(url_list) > 0:
	x = 0
	def next_client(response, url_body, url_list, x, complete_callback):
		if not response.error: url_body[url_list[x]] = response.body

		if len(url_list)-1 == x: complete_callback()
		else: http_client.fetch(url_list[x+1],
					lambda response: 
						next_client(response, url_body, url_list, x+1, complete_callback))

	http_client.fetch(url_list[x],lambda response: next_client(response, url_body, url_list, x, all_call_completes));

tornado.ioloop.IOLoop.instance().start();