presto-main/src/main/java/io/prestosql/operator/InterpretedHashGenerator.java/InterpretedHashGenerator/InterpretedHashGenerator
class InterpretedHashGenerator:    public InterpretedHashGenerator(List<Type> hashChannelTypes, int[] hashChannels)
    {
        this.hashChannels = requireNonNull(hashChannels, "hashChannels is null");
        this.hashChannelTypes = ImmutableList.copyOf(requireNonNull(hashChannelTypes, "hashChannelTypes is null"));
        checkArgument(hashChannelTypes.size() == hashChannels.length);
    }