presto-main/src/main/java/io/prestosql/sql/planner/SystemPartitioningHandle.java/SystemPartitioningHandle/getPartitionFunction
class SystemPartitioningHandle:    public PartitionFunction getPartitionFunction(List<Type> partitionChannelTypes, boolean isHashPrecomputed, int[] bucketToPartition)
    {
        requireNonNull(partitionChannelTypes, "partitionChannelTypes is null");
        requireNonNull(bucketToPartition, "bucketToPartition is null");

        BucketFunction bucketFunction = function.createBucketFunction(partitionChannelTypes, isHashPrecomputed, bucketToPartition.length);
        return new BucketPartitionFunction(bucketFunction, bucketToPartition);
    }