code: def get_fields(upd, bot_ident):
      
      msg = upd.get('message', {})
      text = msg.get('text')
      if not text:
          return
      chat_id = msg['chat']['id']
      command = filter_commands(text, chat_id, bot_ident)
      if not command:
          return
      return (upd['update_id'], chat_id, msg['message_id'], command)
docs: In telegram api, not every update has message field,
      and not every message has update field.
      We skip those cases. Rest of fields are mandatory.
      We also skip if text is not a valid command to handler.