def postOrderTraversal(self, index):
    if (index > self.lastUsedIndex):
        return
    self.postOrderTraversal((index * 2))
    self.postOrderTraversal(((index * 2) + 1))
    print(self.customList[index])
def postOrderTraversal(self, index):
    if (index > self.lastUsedIndex):
        return
    self.postOrderTraversal((index * 2))
    self.postOrderTraversal(((index * 2) + 1))
    print(self.customList[index])