on user leave voice channel discord.py code example

Example 1: python discord bot join voice channel

@bot.command()
async def join(ctx):
    channel = ctx.author.voice.channel
    await channel.connect()
@bot.command()
async def leave(ctx):
    await ctx.voice_client.disconnect()

Example 2: python discord mention user

await message.channel.send(message.author.mention)