How to add chat to telegram via pyrogram?

Question

Python

How to add chat to telegram via pyrogram using its id?
I tried with
app.add_chat_members(chat_id, user_id)
But for some reason it returns the error pyrogram.errors.exceptions.bad_request_400.UsernameNotOccupied: [400 USERNAME_NOT_OCCUPIED]: The username is not occupied by anyone (caused by "contacts.ResolveUsername") , even though there are definitely users with that id , as they have just been received from another group

Answer 1

You may be entering the chat ID in the wrong format. The fact is that the ID formats in Telegram differ between the Bot API and the MT-Proto API. To work with Pyrogram, you need a chat ID in the MT-Proto API format.
For example, the t.me/BotTalk chat has ID 1311056733 (MT-Proto) and -1001311056733 (Bot API). In order to convert the ID to MT-Proto format, you need to take the number with the opposite sign (remove the minus) and subtract 1000000000000 from it