presto-hive/src/main/java/io/prestosql/plugin/hive/HiveTableProperties.java/HiveTableProperties/getPartitionedBy
class HiveTableProperties:    @SuppressWarnings("unchecked")
    public static List<String> getPartitionedBy(Map<String, Object> tableProperties)
    {
        List<String> partitionedBy = (List<String>) tableProperties.get(PARTITIONED_BY_PROPERTY);
        return partitionedBy == null ? ImmutableList.of() : ImmutableList.copyOf(partitionedBy);
    }