from telethon import TelegramClient
import asyncio
import threading
async def send_message():
loop = asyncio.new_event_loop()
api_id = 555
api_hash = '555555555'
client = TelegramClient('55555555.session', api_id, api_hash, loop=loop)
async with client:
await client.send_message('+55555555', '123')
def go():
asyncio.run(send_message())
threading.Thread(target=go).start()