hoeremover.py

# hoeremover 0.0.1
# NOTE: I suggest not using your main Telegram account for creating bots
# DEPENDENCIES: Install `telethon` via pip

from telethon.sync import TelegramClient, events
from telethon.tl.functions.channels import GetMessagesRequest
from telethon.tl.functions.users import GetFullUserRequest

# Doesn't really matter
session_name = 'hoeremover'

# Get from https://my.telegram.org/auth
app_id = 123456
api_hash = 'abcdefg123456'

# Get from @BotFather on Telegram
bot_token = '123456789:bguisberniguhbrseiughers9p8'

with TelegramClient(session_name, app_id, api_hash).start(bot_token=bot_token) as client:
   async def ban_user(client, chat_id, from_id):
      msg = await client.edit_permissions(chat_id, from_id, view_messages=False)
      if len(msg.updates) > 0 and msg.updates[0].id:
         await client.delete_messages(chat_id, msg.updates[0].id)

   @client.on(events.ChatAction)
   async def handler(event):
      if event.user_joined and event.action_message and event.action_message.from_id:
         full_user = await event.client(GetFullUserRequest(id=event.action_message.from_id.user_id))
         if full_user.full_user.personal_channel_message and full_user.chats and len(full_user.chats) > 0:
            chat_title = full_user.chats[0].title
            
            # Most bots are caught by this, no need for another request
            if "Secret Place" in chat_title and "18+" in chat_title:
               await ban_user(event.client, event.chat_id, event.action_message.from_id);
            else: # Check first channel message for t.me links instead
               messages = await event.client(
                  GetMessagesRequest(full_user.chats[0], [full_user.full_user.personal_channel_message])
               )
               if messages.count > 0 and messages.messages and messages.messages[0].message:
                  msg_content = messages.messages[0].message
                  if "t.me/" in msg_content:
                     await ban_user(event.client, event.chat_id, event.action_message.from_id);

   client.run_until_disconnected()