如何在peewee中创建自引用多对多字段？

from peewee import *

database = SqliteDatabase('my_database.db')

class User(Model):
    name = CharField()
    friends = ManyToManyField('self', backref='friends')

    class Meta:
        database = database

database.create_tables([User])

# 创建用户对象
user1 = User.create(name='User 1')
user2 = User.create(name='User 2')
user3 = User.create(name='User 3')

# 建立朋友关系
user1.friends.add(user2)
user1.friends.add(user3)

# 获取用户的朋友列表
friends = user1.friends

for friend in friends:
    print(friend.name)