title: PythonBot - pass argument to command hanlder
body: <p>I'm playing a little bit with Python Telegram Bot, I want to pass to my handler an argument obtained with previous computation, e.g:</p>
  
  <pre><code>def my_handler(bot, update, param):
      print(param)
  
  def main():
      res = some_function()
      updater.dispatcher.add_handler(CommandHandler('cmd', my_handler))
  </code></pre>
  
  <p>How do I pass param to the handler?</p>