Does it support transaction for modules in this project?

[JulianChenlol]

Does it support transaction for modules in this project?
For example: the create method in cost_mode\service.py

def create(*, db_session, cost_model_in: CostModelCreate) -> CostModel:
# xxxx
cost_model = CostModel(
**cost_model_in.dict(exclude={"activities", "project"}),
activities=[],
project=project,
)

db_session.add(cost_model)
db_session.commit()

# Create activities after the cost model is created.
# We need the cost model id to map to the activity.
if cost_model and cost_model_in.activities:
    for activity_in in cost_model_in.activities:
        activity_out = cost_model_service.create_cost_model_activity(
            db_session=db_session, cost_model_activity_in=activity_in
        )
        if not activity_out:
            log.error("Failed to create cost model activity. Continuing.")
            continue

        cost_model.activities.append(activity_out)

db_session.commit()
return cost_model

I checked the definition of db_session in database\core.py, but didn't found such as rollback or with begin.

def get_db(request: Request):
return request.state.db
DbSession = Annotated[Session, Depends(get_db)]

How could it use transaction for 2 commits in 1 operation?
I am learning this project for fastapi practice. Thanks for reply!