docs: def remove_board(board_id):
      """remove board.
  
      :param board_id: board id (e.g. 'diecimila')
      :rtype: None
  
      """
  
      log.debug('remove %s', board_id)
      lines = boards_txt().lines()
      lines = filter(lambda x: not x.strip().startswith(board_id + '.'), lines)
      boards_txt().write_lines(lines)