Python SQLAlchemy：从两个外键定义复合主键

Question

这是我的桌子：

CREATE TABLE  "public"."patient_has_doctor" (
  "patient_person_id" INT  NOT NULL,
  "doctor_person_id" INT  NOT NULL,
  PRIMARY KEY ("patient_person_id", "doctor_person_id"),
  CONSTRAINT "fk_Patient_has_Doctor_Patient1"
    FOREIGN KEY ("patient_person_id")
    REFERENCES "public"."patients" ("person_id")
    ON DELETE CASCADE
    ON UPDATE CASCADE,
  CONSTRAINT "fk_Patient_has_Doctor_Doctor1"
    FOREIGN KEY ("doctor_person_id")
    REFERENCES "public"."doctor" ("person_id")
    ON DELETE CASCADE
    ON UPDATE CASCADE);

我不确定如何在sqlalchemy中定义主键。我知道如何根据Stack上的其他帖子进行外键，但是这种特殊情况使我难以理解。我的猜测是：

class Book(Base):
    __tablename__ = 'books'
    author_firstName = Column(String(20))
    author_lastName = Column(String(20))
    __table_args__ = (ForeignKeyConstraint([author_firstName, author_lastName],
                                           [Author.firstName, Author.lastName]),
                      {}, primary_key=True)

但是我不确定这是否是最好的方法。 来源：Relations on composite keys using sqlalchemy