is_online.py

import asyncio

from telethon import TelegramClient
from telethon.tl import functions
from telethon.tl.types import UserStatusOnline, UserStatusOffline


async def authorize(client):
    is_authorized = await client.is_user_authorized()
    if not is_authorized:
        number = ''
        await client.send_code_request(number)
        code = input('Enter code: ')
        await client.sign_up(code, 'name', 'surname')


async def get_user_status(user_id):
    API_HASH = ''
    API_ID = 0

    client = TelegramClient('online_status', API_ID, API_HASH)

    await client.connect()
    await authorize(client)
    await client.start()

    account = await client(functions.users.GetFullUserRequest(
        id=user_id
    ))

    account_ = await client.get_entity(account.full_user.id)
    print(account_)
    status = account_.status
    if isinstance(status, UserStatusOnline):
        is_online = True
    elif isinstance(status, UserStatusOffline):
        is_online = False
    else:
        is_online = None
    return is_online


if __name__ == '__main__':
    print(asyncio.run(get_user_status('yevheniiku')))