comefrom: <doocs>0110.Balanced Binary Tree_1.py
code: def height(root):
      if root is None:
          return 0
      l, r = height(root.left), height(root.right)
      if l == -1 or r == -1 or abs(l - r) > 1:
          return -1
      return 1 + max(l, r)
masked: def sample_funcname ( var_1 ) :
      if var_1 is None :
          return 0
      var_5 , var_7 = var_0 ( var_1.left ) , var_0 ( var_1.right )
      if var_5 == - 1 or var_7 == - 1 or abs ( var_5 - var_7 ) > 1 :
          return - 1
      return 1 + max ( var_5 , var_7 )
  