from telethon import TelegramClient
import asyncio

api_id =   # Your API_ID
api_hash = ""  # Your APP_ID
bot_token = ""  # via botfather
group_id = 


async def get_users(client, group_id):
    async for user in client.iter_participants(group_id):
        if not user.deleted and not user.bot:
            print("id:", user.id, "username:", user.username, "first_name:", user.first_name)


bot = TelegramClient('bot', api_id, api_hash).start(bot_token=bot_token)

with bot:
    asyncio.get_event_loop().run_until_complete(get_users(bot, group_id))