优先级队列(python)

class PriorQueque:
    def __init__(self, list1=[]):
        self.__list = []
        self.__MakeMaxHeap(list1)
    
    def __HeapUp(self):
        curIndex = len(self.__list) - 1 #tail element
        parentIndex = (curIndex-1)//2
        while(parentIndex >= 0 and self.__list[curIndex] > self.__list[parentIndex]):
            self.__list[curIndex], self.__list[parentIndex] = 
            self.__list[parentIndex], self.__list[curIndex]
            curIndex = parentIndex
            parentIndex = (curIndex-1)//2
        
    def __HeapDown(self):
        retValue = self.__list[0]
        self.__list[0] = self.__list.pop()
        disorderValue = self.__list[0]
        lastIndex = len(self.__list) - 1
        bigIndex = 0
        curIndex = 0 
        leftIndex = 2 * curIndex + 1 
        while(leftIndex <= lastIndex):
            bigIndex = leftIndex
            if(leftIndex < lastIndex and self.__list[leftIndex] < self.__list[leftIndex + 1]):
                bigIndex = leftIndex + 1
            if(disorderValue >= self.__list[bigIndex]):
                break
            self.__list[curIndex] = self.__list[bigIndex]
            curIndex = bigIndex
            leftIndex = 2 * curIndex + 1
        self.__list[curIndex] = disorderValue
        return retValue

    def Pop(self):
        if(len(self.__list) <= 2):
            return self.__list.pop()
        else:
            return self.__HeapDown()
    
    def Push(self, value):
        self.__list.append(value)
        self.__HeapUp()

    def Top(self):
        return self.__list[0]

    def __MakeMaxHeap(self, list1):
        for i in list1:
            self.Push(i)

    def __repr__(self):
        return self.__list.__repr__()