code: def get_replies_to(self, msg):
          
          mid = msg.get_message_id()
          msg_hash = self.get_messages()
          for m in msg_hash.keys():
              if m.get_message_id() == mid:
                  return msg_hash[m]
          return None
docs: returns all replies to the given message contained in this thread.
  
          :param msg: parent message to look up
          :type msg: :class:`~alot.db.message.Message`
          :returns: list of :class:`~alot.db.message.Message` or `None`