I want to you be a  python Telethon library code helper. You need help me to write a telegram client use telethon library.
which functions I need are: 

1. login 
2. list chats list of login user
3. list top 3 messages of those chat and show message content as text
4. do not exist the process, waiting for new message, when new message arrive, display new message content

that's all, If I have more requests, I will tell you later Avoid using the following keywords: message, code, list, chat
user