presto-redis/src/main/java/io/prestosql/plugin/redis/RedisTableFieldGroup.java/RedisTableFieldGroup/RedisTableFieldGroup
class RedisTableFieldGroup:    @JsonCreator
    public RedisTableFieldGroup(
            @JsonProperty("dataFormat") String dataFormat,
            @JsonProperty("name") String name,
            @JsonProperty("fields") List<RedisTableFieldDescription> fields)
    {
        this.dataFormat = requireNonNull(dataFormat, "dataFormat is null");
        this.name = name;
        if (!dataFormat.equals("set") && !dataFormat.equals("zset")) {
            this.fields = ImmutableList.copyOf(requireNonNull(fields, "fields is null"));
        }
        else {
            this.fields = null;
        }
    }