SQLAlchemy Query for Child Objects in One to Many Self Referential Relationship

Finding the answer to a rather simple question proved to be shockingly difficult.

How to query such that parent objects include all child objects in a one to many relationship using SQLAlchemy?

Here’s a contrived example:

class ProductTest(Base):
    __tablename__ = 'products_test'
    product_id=Column(BigInteger, autoincrement=True, primary_key=True)
    parent_variant = Column(BigInteger, ForeignKey('products_test.product_id'))
    price=Column('price', Float, default=0.0)
    product=Column('product', String(255))
    variants = relationship('ProductTest', lazy="joined", join_depth=2)

The important part is this:

variants = relationship('ProductTest', lazy="joined", join_depth=2) 

Notice the lazy and join_depth attributes.