@commands.command() # uses command decorators, in this case inside a cog
@commands.has_permissions(ban_members=True) # only people that have permissions to ban users can use this command
async def ban(self, ctx, user: discord.Member, *, reason): # The person banning someone has to ping the user to ban, and input a reason. Remove self if you are outside a cog.
    await ctx.guild.ban(user, reason=reason) # Bans the user.
    await user.send(f"You have been banned in {ctx.guild} for {reason}") # Private messages user.
    await ctx.send(f"{user} has been successfully banned.") # messages channel to tell everyone it worked