comefrom: <qiyuangong>156_Binary_Tree_Upside_Down_1.py
code: def upsideDownBinaryTree( root):
      node, parent, parentRight = root, None, None
      while node is not None:
          left = node.left
          node.left = parentRight
          parentRight = node.right
          node.right = parent
          parent = node
          node = left
      return parent
masked: def sample_funcname ( var_0 ) :
      var_1 , var_3 , var_4 = var_0 , None , None
      while var_1 is not None :
          left = var_1.left
          var_1.left = var_4
          var_4 = var_1.right
          var_1.right = var_3
          var_3 = var_1
          var_1 = left
      return var_3
  