Why can't I get information about the user by id in the telethon library, but I can get information about the user through @name?

Question

Python

Sample code I use

from telethon import TelegramClient, sync
import myhelper
import socks
from telethon.tl.types import PeerUser, PeerChat, PeerChannel

config_f = myhelper.open_yaml('config.yaml')

client = TelegramClient("my_sessia", config_f["id"], config_f["hash"])
client.start()
client.connect()
print(client.get_entity((615435914)))

I use these versions:
Telethon==1.1.1
Telethon-sync==1.0.4
writes an error:

ValueError: Could not find the input entity for "615435914". Please read https://telethon.readthedocs.io/en/latest/extra/ba... to find out more details.

Answer 1

It is impossible (or possible, but this is not mentioned anywhere) to get information about a "foreign" user by id.
But, if we wrote to him at least once and we still have a dialogue with him, then first you need to call client.get_dialogs()so that the client "remembers" the users.
After that it client.get_entity(id)will work fine.