many to many relationship in sqlalchemy - python-3.x

Question

need a little help. I have two table with many to many relation between them . Now i am not using any of those sqlalchemy orm relationship because of certain constraints in the project.
class ChargeStation(Base):
__tablename__="charge_station"
__table_args__={'extend_existing': True}
station_id=Column(String(255),primary_key=True,index=True)
station_name=Column(String(255))
address=Column(String(255),nullable=True)
class TariffChart(Base):
__tablename__="tariff_chart"
__table_args__={'extend_existing': True}
tariff_id=Column(String(30),primary_key=True,index=True)
tariff_name=Column(String(30))
rate=Column(Float(25),nullable=True)
class StationTariff(Base):
__tablename__="station_tariff"
__table_args__={'extend_existing': True}
id=Column(UUID(as_uuid=True),primary_key=True,default=uuid4)
station_id=Column(String, ForeignKey("charge_station.charge_station_id",ondelete="CASCADE"),nullable=True)
tariff_id=Column(String, ForeignKey("tariff_chart.tariff_id",ondelete="CASCADE"),nullable=True)
datetime=Column(DateTime(), default=datetime.now())
I want to fetch all rate cards assigned to every stations through a get call . For that i am using the below query.
charge_stations=db.query(station.station_id,
station.station_name,
station.address,tariff).\
join(station_tariff,station.station_id==station_tariff.station_id).\
join(tariff,station_tariff.tariff_id==tariff.tariff_id).all()
Now i am getting the response as this
[
{
"station_id": "1",
"station_name": "s1",
"address": "abc",
"tariff_chart": {
"tariff_id": "t1",
"rate": 30,
"tariff_name": "tar1"
}
},
{
"station_id": "1",
"station_name": "s1",
"address": "abc",
"tariff_chart": {
"tariff_id": "t2",
"rate": 30.6,
"tariff_name": "tar2"
}
},
{
"station_id": "23",
"station_name": "Groot",
"address": "xyz ",
"tariff_chart": {
"tariff_id": "t1",
"rate": 30,
"tariff_name": "tar1"
}
}
]
But i want all the tariff chart related to particular station clubbed together in a list of dictionaries like this
[
{
"station_id": "1",
"station_name": "s1",
"address": "abc",
"tariff_chart":[ {
"tariff_id": "t1",
"rate": 30,
"tariff_name": "tar1"
},
{
"tariff_id": "t2",
"rate": 30.6,
"tariff_name": "tar2"
}]
},
{
"station_id": "23",
"station_name": "Groot",
"address": "xyz ",
"tariff_chart": {
"tariff_id": "t1",
"rate": 30,
"tariff_name": "tar1"
}
}
]
Can you guys please suggest how to achieve that .