class ScoreBoard:

""" Fixed-length sequence of high scores in nondecreasing order. """

def __init__(self, capacity=10):

""" initialize scoreboard with given maximum capacity. All entries are initially None.

"""

self._board = [None]*capacity # reserve space for future scores

self._n = 0 # number of actual entries

def __getitem__(self, k):

""" Return entry at index k."""

return self._board[k]

def __str__(self):

""" Return string representation of the high score list. """

return '\n'.join(str(self._board[j]) for j in range(self._n))

def add_score(self, entry):

"""Consider adding entry to high scores."""

score = entry.get_score()

# Does new entry qualify as a high score?

# answer is yes if board not full or score is higher than last entry

yes = self._n < len(self._board) or score > self._board[-1].get_score()

if yes:

if self._n < len(self._board): #no score drops from list

self._n += 1

# shift lower scores rightward to make room for new entry

j = self._n -1

while j > 0 and self._board[j-1].get_score() < score:

self._board[j] = self._board[j-1] # shift entry from j-1 to j

j -= 1 # and decrement j

self._board[j] = entry