from telegram.ext import Updater
  updater = Updater(token='xxx')

  dispatcher = updater.dispatcher

  import logging
  logging.basicConfig(format='%(asctime)s - %(name)s - %(levelname)s - %(message)s', level=logging.INFO)

  def start(update, context):
         context.bot.send_message(chat_id=update.message.chat_id, text="I'm a bot, please talk to me!")

 from telegram.ext import CommandHandler
 start_handler = CommandHandler('start', start)
 dispatcher.add_handler(start_handler)

 updater.start_polling()