Discord.py how to stop single and multiple loops?

Question

Python

I need to make it so that there is a command that stops a certain cycle or all cycles at once. I wrote the code, but it doesn't work...

import discord
from discord.ext import commands

client = commands.Bot(command_prefix='!')


global stop1


@client.command(pass_context=True)
async def stopp(ctx):
    #global stop1
    stop1 = True


@client.command(pass_context=True)
async def test1(ctx):
    stop1 = False
    while True:
        await ctx.send('Test')
        if stop1 == True:
            break

client.run ("TOKEN")

I tried to put global in place of the comment - it doesn't work. There is no error at all, but the code is not working, what's the problem?