[Python] Discord.py, commands.error: "roll" not found

I just started studying Python this week and I don't understand what I'm doing wrong. My discord bot is online, but every time I try to type a command in Discord it pings back to VS Code as

"discord.ext.commands.errors.CommandNotFound: Command "roll" is not found Ignoring exception in command None:

It's not just roll command, it doesn't seem to be registering any commands. What should I do?

import discord
from discord.ext import commands
import random

TOKEN = 'token hidden'

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

@bot.event
async def on_ready():
print(f'We have logged in as {bot.user}')

@bot.command()
async def ping(ctx):
await ctx.send('Pong!')

@client.command()
async def roll(ctx, dice: str):
"""Rolls a dice in NdN format."""
try:
rolls, limit = map(int, dice.split('d'))
except Exception:
await ctx.send('Format has to be in NdN!')
return

result = ', '.join(str(random.randint(1, limit)) for r in range(rolls))
await ctx.send(result)

bot.run(TOKEN)

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