如何在SQLALchemy中执行左连接？

from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship
from sqlalchemy import join

engine = create_engine('数据库连接字符串')
Session = sessionmaker(bind=engine)
session = Session()

Base = declarative_base()

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    orders = relationship("Order", back_populates="user")

class Order(Base):
    __tablename__ = 'orders'
    id = Column(Integer, primary_key=True)
    user_id = Column(Integer, ForeignKey('users.id'))
    user = relationship("User", back_populates="orders")

query = session.query(User, Order).join(Order, User.id == Order.user_id, isouter=True)
results = query.all()