Identify the bug in the following code snippet for the Maximum Units on a Truck problem:

Identify the bug in the following code snippet for the Maximum Units on a Truck problem:

def maximumUnits(boxTypes, truckSize):
    boxTypes.sort(key=lambda x: x[1])  # Sort ascending instead of descending
    totalUnits = 0
    for boxes, units in boxTypes:
        if truckSize == 0:
            break
        take = min(boxes, truckSize)
        totalUnits += take * units
        truckSize -= take
    return totalUnits