presto-iceberg/src/main/java/io/prestosql/plugin/iceberg/PartitionFields.java/PartitionFields/parsePartitionFields
class PartitionFields:    public static PartitionSpec parsePartitionFields(Schema schema, List<String> fields)
    {
        PartitionSpec.Builder builder = PartitionSpec.builderFor(schema);
        for (String field : fields) {
            parsePartitionField(builder, field);
        }
        return builder.build();
    }