presto-main/src/main/java/io/prestosql/cost/CostComparator.java/CostComparator/CostComparator
class CostComparator:    @VisibleForTesting
    public CostComparator(double cpuWeight, double memoryWeight, double networkWeight)
    {
        checkArgument(cpuWeight >= 0, "cpuWeight cannot be negative");
        checkArgument(memoryWeight >= 0, "memoryWeight cannot be negative");
        checkArgument(networkWeight >= 0, "networkWeight cannot be negative");
        this.cpuWeight = cpuWeight;
        this.memoryWeight = memoryWeight;
        this.networkWeight = networkWeight;
    }