在SQLAlchemy中，如何在生成的SQL中保留同义词的名称作为别名(SQL AS)？

from sqlalchemy import create_engine, select, func
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String

# 创建数据库连接
engine = create_engine('mysql+pymysql://username:password@host:port/database')
Session = sessionmaker(bind=engine)
session = Session()

# 创建映射类
Base = declarative_base()

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    name = Column(String(50))

# 创建同义词别名
user_alias = select([User.name.label('user_name')]).alias()

# 查询使用同义词别名
query = session.query(user_alias.c.user_name, func.count(user_alias.c.user_name)).group_by(user_alias.c.user_name)
result = query.all()

# 打印结果
for row in result:
    print(row.user_name, row[1])