void readRowGroup(std::shared_ptr<RowGroupReader> &group_reader, graph_statistics &stats) {
  for (int col = 0; col < group_reader->num_columns(); col++) {
    std::shared_ptr<ColumnReader> column = group_reader->Column(col);
    if (column->descr()->name() == "degree") {
      std::shared_ptr<Int32Reader> column_reader = std::dynamic_pointer_cast<Int32Reader>(column);
      while (column_reader->HasNext()) {
        readBatch(column_reader, stats);
      }
      // There is only one degree column, so we can skip the other ones in the RowGroup.
      break;
    }
  }
}