How do I change the volume of my discord bot with python?

I want the user to be able to change the volume of my discord music bot. I have tried doing it, but it does not seem to work. I already defined vc as "something" outside, and then used it to play music in try and except. I wonder if that is causing the problem.

elif contents.startswith("volume"):
            volume = contents
            volume = volume.strip("volume ")
            volume = int(volume)

            if volume <= 100:
                volume = volume / 10
                vc.source = discord.PCMVolumeTransformer(vc.source)
                vc.source.volume = volume
            else:
                message.channel.send("Please give me a number between 0 and 100!")

Solution

PCMVolumeTransformer is expecting a float between 0 and 1.0.

The initial setting of the PCMVolumeTransformer should include the volume and should be placed right after your vc.play(). Like vc.source = discord.PCMVolumeTransformer(vc.source, volume=1.0)

Then in your message processing you can try something like:

** Updated to avoid using a global for the voice ('vc') connection by adding a voice connect function. Please note that this function is only for the volume message. The original connection to play the audio is separate is still in use.

    if message.content.lower().startswith('volume '):
        new_volume = float(message.content.strip('volume '))
        voice, voice.source = await voice_connect(message)
        if 0 <= new_volume <= 100:
            new_volume = new_volume / 100
            voice.source.volume = new_volume
        else:
            await message.channel.send('Please enter a volume between 0 and 100')

@bot.command()
async def voice_connect(message):
    if message.author == bot.user:
        return

    channel = message.author.voice.channel
    voice = get(bot.voice_clients, guild=message.guild)

    if voice and voice.is_connected():
        return voice, voice.source
    else:
        voice = await channel.connect()
        voice.source = discord.PCMVolumeTransformer(voice.source, volume=1.0)
        print(f"The bot has connected to {channel}\n")

    return voice, voice.source