text: from discord.ext import commands
  
  class Upload(commands.Cog):
      def __init__(self, bot, config):
          self.bot = bot
          self.bot.add_listener(self.on_message, "on_message")
  
      async def on_message(self, message):
          if message.author == self.bot.user:
              return
  
          if len(message.attachments) > 0:
              filename = message.attachments[0].filename.replace('/(?:\.(?![^.]+$)|[^\w.])+/g', '-').lower()
              if filename.endswith('.mp3'):
                  await message.attachments[0].save('uploads/audio/' + filename)
                  await message.channel.send('Arquivo: `' + filename + '` enviado com sucesso.')
          return
  
          #await self.bot.process_commands(message)