Check if user is in a voice channel discord.py

I am making a bot that will play sounds in a vc. I have made the code to join the call, play the mp3, then leave the call but when the user is not in a call I get this error:

Ignoring exception in command ring:
Traceback (most recent call last):
  File "C:\Users\max\AppData\Roaming\Python\Python39\site-packages\discord\ext\commands\core.py", line 85, in wrapped
    ret = await coro(*args, **kwargs)
  File "C:\Users\max\OneDrive\Desktop\Code\DiscordBots\Nokia\Nokia.py", line 91, in ring
    channel = ctx.author.voice.channel
AttributeError: 'NoneType' object has no attribute 'channel'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Users\max\AppData\Roaming\Python\Python39\site-packages\discord\ext\commands\bot.py", line 903, in invoke
    await ctx.command.invoke(ctx)
  File "C:\Users\max\AppData\Roaming\Python\Python39\site-packages\discord\ext\commands\core.py", line 859, in invoke
    await injected(*ctx.args, **ctx.kwargs)
  File "C:\Users\max\AppData\Roaming\Python\Python39\site-packages\discord\ext\commands\core.py", line 94, in wrapped
    raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: AttributeError: 'NoneType' object has no attribute 'channel'

This is my code that I have so far:

@client.command()
async def ring(ctx):
    channel = ctx.author.voice.channel
    vc = await channel.connect()
    vc.play(discord.FFmpegPCMAudio("Audio/NokiaRingtone.mp3"))
    time.sleep(5)
    await ctx.voice_client.disconnect()

If anyone could help me check if the user is in a voice channel that would be great.

You can simply check if it's not a nonetype with an if statement

@bot.command()
async def foo(ctx: commands.context.Context):
    voice_state = ctx.author.voice

    if voice_state is None:
        # Exiting if the user is not in a voice channel
        return await ctx.send('You need to be in a voice channel to use this command')

    # Put the rest of the code here

Reference