bool RemoveLeafFromSelf(Leaf leaf)
 {
     if (DoRemoveLeafFromSelf(leaf))
     {
         return(true);
     }
     return(_root.RemoveLeafInTotalTree(leaf));
 }
 bool RemoveLeafInTotalTreeFromChindren(Leaf leaf)
 {
     if (_upperRightChild.RemoveLeafInTotalTree(leaf))
     {
         return(true);                                    //如果子节点移除成功了,那就说明不需要继续遍历剩下的节点了,直接返回 true
     }
     if (_lowerRightChild.RemoveLeafInTotalTree(leaf))
     {
         return(true);
     }
     if (_lowerLeftChild.RemoveLeafInTotalTree(leaf))
     {
         return(true);
     }
     if (_upperLeftChild.RemoveLeafInTotalTree(leaf))
     {
         return(true);
     }
     return(false);
 }