old_contents: import discord
  import asyncio
  
  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):
      if message.content.startswith('!test'):
          await client.send_message(message.channel, 'Hello world!')
  
  client.run('paste_token_here')
new_contents: import asyncio
  
  import discord
  from   discord.ext import commands
  
  
  
  bot = commands.Bot(command_prefix='!', description='test')
  
  @bot.event
  async def on_ready():
      print('Logged in as')
      print(bot.user.name)
      print(bot.user.id)
      print('------')
      
  @bot.command()
  async def test():
      await bot.say('Hello World!')
  
  bot.run('paste_token_here')
  
subject: Switch to Bot object instead of Client