Identify possible objects in the following system, and draw a UML object diagram. You may make any reasonable assumptions about the system.

A petrol (gas) station is to be set up for fully automated operation. Drivers swipe their credit card through a reader connected to the pump, the card is verified by communication with a credit company computer and a fuel limit established. The driver may then take the fuel required. When fuel delivery is complete and the pump hose is returned to its holster, the driver's credit card account is debited with the cost of the fuel taken. The credit card is returned after debiting. If the card is invalid, it is returned by the pump before fuel is dispensed.