Multi-turn user requests:
user: I require assistance with my car. Can you kindly ensure that the fuel tank is refilled with precisely 38 liters of petrol? Make sure using 2 decimal digit for gallon amount.
user: Wonderful, with the fuel tank now adequately replenished, proceed to activate the engine in "START" mode. Convey to me the operational status of the engine, the voltage of the battery, the AC speed and the fan speed.

Tools involved: VehicleControlAPI
MathAPI
Expected function-call sequence: VehicleControlAPI.liter_to_gallon
VehicleControlAPI.fillFuelTank
VehicleControlAPI.startEngine
MathAPI.mean