class SchemaUpdate implements UpdateSchema {

  private static List<Types.NestedField> addFields(List<Types.NestedField> fields,
                                                   Collection<Types.NestedField> adds) {
    List<Types.NestedField> newFields = Lists.newArrayList(fields);
    newFields.addAll(adds);
    return newFields;
  }

    SchemaUpdate(TableOperations ops);
    SchemaUpdate(Schema schema, int lastColumnId);

}