使用back-populate在SQLAlchemy ORM中获取记录

Question

我有两个代表表A和B的类，如下所示

from sqlalchemy.ext.declarative import declarative_base

Class A(Base):
  __tablename__ = 'a'
    id = Column("user_id", Integer, primary_key=True)
    name = Column("user_name", String)
    products = relationship("B", back_populates = "users")

Class B(Base):
   __tablename__ = 'b'
    id = Column("prod_id", Integer, primary_key=True)
    name = Column("user_name", String)
    users = realtionship("A", back_populates = "products")

我想使用属性产品/用户访问购买产品的所有用户，反之亦然。任何想法如何在不使用会话的情况下完成？