python discord music bot

1There were some changes to youtube_dl and FFmpeg, so this should work.
2
3import discord
4
5import youtube_dl
6
7from discord.ext import commands
8
9ydl_opts = {
10    'format': 'bestaudio/best',
11    'postprocessors': [{
12        'key': 'FFmpegExtractAudio',
13        'preferredcodec': 'mp3',
14        'preferredquality': '192',
15    }],
16}   
17
18def endSong(guild, path):
19    os.remove(path)                                   
20
21@cat.command(pass_context=True)
22async def play(ctx, url):
23    if not ctx.message.author.voice:
24        await ctx.send('you are not connected to a voice channel')
25        return
26
27    else:
28        channel = ctx.message.author.voice.channel
29
30    voice_client = await channel.connect()
31
32    guild = ctx.message.guild
33
34    with youtube_dl.YoutubeDL(ydl_opts) as ydl:
35        file = ydl.extract_info(url, download=True)
36        path = str(file['title']) + "-" + str(file['id'] + ".mp3")
37
38    voice_client.play(discord.FFmpegPCMAudio(path), after=lambda x: endSong(guild, path))
39    voice_client.source = discord.PCMVolumeTransformer(voice_client.source, 1)
40
41    await ctx.send(f'**Music: **{url}')
42Optional, useful function
43If you want you can make your bot leave the voice channel after the song/music stop playing. Add this at the end of your code.
44
45while voice_client.is_playing():
46        await asyncio.sleep(1)
47    else:
48        await voice_client.disconnect()
49        print("Disconnected")
50If something wouldn't work
51If you had any problem with understanding the code or something wouldn't work, comment under my answer and I'll try my best to help you. Btw if you are thinking about hosting your bot on Heroku I can help you with that, because there are some things you need to do to make your music bot run there.