Combining Dependencies in FastAPI using Sub-Dependencies

Question

I would like to combine 2 Dependencies in FastAPI to implement Nested Model

Following is the relevant code:

def car_params(name: Union[str, None], brand: Union[str, None]):
    return {"name": name, "brand": brand}
def motor_params(name_m: Union[str, None], brand_m: Union[str, None]):
    return {"name_m": name_m, "brand_m": brand_m}

# nested schema
def transport_param(
    car: Annotated[dict, Depends(car_params)],
    motor: Annotated[dict, Depends(motor_params)],
):
    if not car:
        return motor
    else:
        return car

@app.post("/cardetail/3")
def get_car(
    info: Annotated[dict, Depends(transport_param)],
):
    return info

I tried running the endpoint on Docs, but it shows the loading too long!

Is the implementation wrong?

Thanks.