def _apply_jump(board, move):
    """Apply a jump move to a given board.

    Args:
      board: board string
      move: move tuple

    Returns:
      Board string of new position.
    """
    assert (board[move[0]].lower() == 'b')
    board_list = list(board)
    board_list[move[-1]] = board_list[move[0]]
    if move[-1] > 27:  # King the piece if necessary.
        board_list[move[-1]] = board_list[move[-1]].upper()
    board_list[move[0]] = '-'
    # remove the jumped checkers
    for i in move[1::2]:
        board_list[i] = '-'
    return ''.join(board_list)