Delete non-image attachments discord - discord.py

ImagesOnly.py

#!/usr/bin/python
# python 3
# requires https://github.com/Rapptz/discord.py / "pip install discord.py"
# licensed under the MIT license. For more information view LICENSE.md

import discord
import asyncio
import os.path
import re
import sys
from pathlib import Path

# CONFIG START -------
whiteList = ['bmp','jpeg','jpg','png']
# CONFIG END -------


client = discord.Client()


@client.event
async def on_ready():
    print('Logged in as')
    print(client.user.name)
    print(client.user.id)
    print('------')


@client.event
async def on_message(message):
    try:
      for attachment in message.attachments:
        if attachment['filename'].split('.')[-1] not in whiteListArray:
          client.delete_message(message)
        
    except:
        print('Unknown error')


if os.path.exists('token.txt'):
    tokenfile = open('token.txt', 'r')
    token = tokenfile.read()
    tokenfile.close()
    client.run(token)

else:
    token = input('Please input token: ')
    os.system('cls' if os.name == 'nt' else 'clear')
    client.run(token)