docs: def xlsw_write_row(ws, row_idx, row, fmt=None):
      """
      ws:
      row_idx: row number
      row: a list, data to write
      fmt: format for cell
      """
      for col_idx in range(len(row)):
          ws.write(row_idx, col_idx, row[col_idx], fmt)
      row_idx += 1
      return row_idx