'Drop n lowest dice from the result.
Args:
n: the number of dice to drop.'

def drop_lowest(self, n):

    sorted_x = sorted(self.dice.items(), key=operator.itemgetter(0))
    for (i, count) in sorted_x:
        count = self.dice[i]
        if (n == 0):
            break
        elif (n < count):
            self.dice[i] = (count - n)
            self.dropped[i] = n
            break
        else:
            self.dice[i] = 0
            self.dropped[i] = count
            n = (n - count)
    for (i, count) in self.dropped.items():
        if (self.dice[i] == 0):
            del self.dice[i]
