Pycord Error: discord.errors.ExtensionFailed: Extension 'cogs.cmds' raised an error: AttributeError: 'Bot' object has no attribute 'add_command'

I am trying to load a cog (located in the cogs directory) but everytime I try to load it I get the following error message:

discord.errors.ExtensionFailed: Extension 'cogs.cmds' raised an error: AttributeError: 'Bot' object has no attribute 'add_command'

I'm doing exacly how the tutorial shows, but it still doesn't work. Here is my code:

# main.py

import discord, os, dotenv

# setup
bot = discord.Bot(
    intents = discord.Intents.default(),
    prefix = "zrun "
)

@bot.event
async def on_ready():
    print(f'Connected as {bot.user}')

# load cmds
bot.load_extension('cogs.cmds')

# get token and run bot
dotenv.load_dotenv()
bot.run(os.getenv('TOKEN'))

The cog file:

# cogs/cmds.py

import discord
from discord.ext import commands

class Cmds(commands.Cog):
    def __init__(self, bot):
        self.bot = bot

    @commands.command()
    async def echo(self, ctx, msg:str):
        """Sends the specified text in the chat"""

        await ctx.send(msg)

def setup(bot):
    bot.add_cog(Cmds(bot))

Yes, I've searched StackOveflow, but no cog-related answers solved my problem.