The following code is for joining a group on telegram:
from telethon.sync import TelegramClient
from telethon import functions, types
with TelegramClient(name, api_id, api_hash) as client:
result = client(functions.messages.ImportChatInviteRequest(
hash='A4LmkR23G0IGxBE71zZfo1'
))
print(result.stringify())
How to leave that group after the work is done?
You could use
client.delete_dialog