Python 如何使用FlaskSQLAlChemy会话，从SQLAlChemy返回一个使用`join`的查询，以将其作为FlaskSession使用

我有以下情况:

我想创建一条路由，它将使用SQLAlChemy中的join函数返回两个models(表)上的列具有相同值的所有行.

我在我的服务中创建的方法如下所示，它还包含可以工作的纯SQL，以供参考:

@staticmethod
def fetch_sectors():
    """
    Fetches all sectors with their respective branches, using an inner join with the equipment table.
    As this is a JOIN involving more than one entity, and not a direct query in the model, it's necessary
    to use the session.query() from SQLAlchemy - https://docs.sqlalchemy.org/en/14/orm/query.html

    The Controller Object responsible for this is db_sql.session, instantiated by Flask's SQLAlchemy.

    Conversion of the below flow to SQL for reference - INNER JOIN + DISTINCT:
    -- JOIN: Show Columns/Records in Common between tables.
    SELECT DISTINCT EQUIPMENT.T9_BRANCH AS sector_branch,
                    SECTORS.T6_CODE AS sector_code,
                    SECTORS.T6_NAME AS sector_name
        FROM ST9010 AS EQUIPMENT
        JOIN ST6010 AS SECTORS ON SECTORS.T6_CODE = EQUIPMENT.T9_CODE;

    :return: All Sectors
    """
    print("Creating the Query, with INNER JOIN + DISTINCT.")
    query = db_sql.session.query(
        Equipment.equipment_branch.label('sector_branch'),
        Sectors.sector_code,
        Sectors.sector_name
    ).join(
        Sectors, Sectors.sector_code == Equipment.equipment_sector
    ).distinct()

    print("Returning the Sectors.")
    return [sector.sectors_to_dict() for sector in query.all()], None

这些是我使用的to_dict种方法的模型:

class Equipment(db_sql.Model):
    __tablename__ = 'ST9010'  # Assets Table - Protheus

    equipment_id: Mapped[int] = mapped_column("T9_EQUIPID", db_sql.Integer, primary_key=True)
    equipment_branch: Mapped[str] = mapped_column("T9_BRANCH", db_sql.String, primary_key=True)
    equipment_sector: Mapped[str] = mapped_column("T9_CODE", db_sql.String, primary_key=True)
    equipment_name: Mapped[str] = mapped_column("T9_NAME", db_sql.String, nullable=False)
    equipment_costcenter: Mapped[str] = mapped_column("T9_COSTCENTER", db_sql.String, nullable=False)
    DELETED: Mapped[str] = mapped_column(db_sql.String, nullable=True)
    T9_STATUS: Mapped[str] = mapped_column(db_sql.String, nullable=True)

    def to_dict(self):
        return {
            "equipment_id": self.equipment_id,
            "equipment_branch": self.equipment_branch,
            "equipment_sector": self.equipment_sector,
            "equipment_name": self.equipment_name,
            "equipment_costcenter": self.equipment_costcenter
        }


class Sectors(db_sql.Model):
    __tablename__ = 'ST6010'  # Families Table - Protheus

    # T6_BRANCH blank: In the Query, do an Inner Join with T9_BRANCH of ST9010
    sector_branch = mapped_column("T6_BRANCH", db_sql.String, primary_key=True)
    sector_code = mapped_column("T6_CODE", db_sql.String, primary_key=True)
    sector_name = mapped_column("T6_NAME", db_sql.String, nullable=False)
    DELETED = mapped_column(db_sql.String, nullable=True)

    def to_dict(self):
        return {
            "sector_branch": self.sector_branch,
            "sector_code": self.sector_code,
            "sector_name": self.sector_name
        }

    @staticmethod
    def sectors_to_dict(result):
        return {
            "sector_branch": result.sector_branch,
            "sector_code": result.sector_code,
            "sector_name": result.sector_name,
            "equipment_branch": result.equipment_branch
        }

当我使用上面的方法fetch_sectors()执行查询时，我从SQLAlchemy Engine得到以下错误:

_key_fallback
    raise KeyError(key) from err
KeyError: 'sectors_to_dict'

_key_not_found
    raise AttributeError(ke.args[0]) from ke
AttributeError: sectors_to_dict

我为SQLAlChemy启用了日志(log)记录，对sqlalchemy.engine使用logging，这是SQLAlChemy生成的SELECT:

INFO:sqlalchemy.engine.Engine:SELECT DISTINCT [ST9010].[T9_BRANCH] AS sector_branch, [ST6010].[T6_CODE] AS [ST6010_T6_CODE], [ST6010].[T6_NAME] AS [ST6010_T6_NAME]
FROM [ST9010] JOIN [ST6010] ON [ST6010].[T6_CODE] = [ST9010].[T9_CODE]

我试着解决这个问题好几个小时了，在StackOverflow上搜索了多个问题，与GPT 4.0交谈了几个小时，阅读了FlaskSQLAlChemy和SQLAlChemy文档，但我觉得我在这里走进了解决方案的死胡同……

这是StackOverflow的一个问题，几乎解决了我的问题，但我无法实现它，大约一个小时后就放弃了:Use Flask-SqlAlchemy to query relationship database

有人能帮帮我吗？