peewee 怎么设置auto_increment ？

from peewee import *


db = SqliteDatabase('test.db')

class User(Model):
    uid = IntegerField(primary_key=True)
    name = CharField()



    class Meta:
        database = db # This model uses the "people.db" database.
 

#db.create_tables([User])
 
username='5576'
try:
    user = User.get(name=username)
    print(user.uid)
except:

   user=User.create(name=username)
   print(user.uid)

Create 输出uid 是None
再次查询就有uid 怎么样在create返回uid 就象mysql last insert id那样