gistfile1.py

   def send_message(self):
        json_data ={"collapse_key":"msg","data":{"data":"xyz",},"registration_ids":['APA91bH2DtFn9494z-*****bMP1BPUsVI8ltb395MNp-39k8sp0',],}

        url ='https://android.googleapis.com/gcm/send'
        myKey ="AIzaSyC********************A7S" 
        data = json.dumps(json_data)
        headers ={'Content-Type':'application/json','Authorization':'key=%s'% myKey}
        req = urllib2.Request(url, data, headers)
        f = urllib2.urlopen(req)
        response = json.loads(f.read())


        self.response.out.write(json.dumps(response,sort_keys=True, indent=2))