如何在discord.py中添加角色？

import discord
from discord.ext import commands

intents = discord.Intents.default()
intents.guilds = True
intents.members = True

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

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

@bot.command()
@commands.has_permissions(manage_roles=True)
async def add_role(ctx, role_name: str, *, permissions: discord.Permissions = None):
    guild = ctx.guild
    if permissions is None:
        permissions = discord.Permissions()
    
    # 检查角色是否已存在
    existing_role = discord.utils.get(guild.roles, name=role_name)
    if existing_role:
        await ctx.send(f'角色 {role_name} 已存在。')
        return
    
    # 创建新角色
    new_role = await guild.create_role(name=role_name, permissions=permissions)
    await ctx.send(f'角色 {role_name} 已创建。')

bot.run('YOUR_BOT_TOKEN')