Attempt Number: 4
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
To move closer to the goal state, we should first clear curb_2 by moving car_2 to the empty curb_1. This will make car_1 clear, allowing further maneuvers.

New State Description:
Curb_0: Car_0 parked, clear. Curb_1: Car_2 parked, clear. Curb_2: Car_1 parked, clear. Curb_3: Car_3 parked, clear. Cars: Car_0 clear, car_1 clear, car_2 clear, car_3 clear.

Action Chosen:
(move-car-to-curb car_2 car_1 curb_1)
