comefrom: <doocs>0129.Sum Root to Leaf Numbers_1.py
code: def dfs(root, presum):
      if root is None:
          return 0
      s = 10 * presum + root.val
      if root.left is None and root.right is None:
          return s
      return dfs(root.left, s) + dfs(root.right, s)
masked: def sample_funcname ( var_1 , var_2 ) :
      if var_1 is None :
          return 0
      var_7 = 10 * var_2 + var_1.val
      if var_1.left is None and var_1.right is None :
          return var_7
      return var_0 ( var_1.left , var_7 ) + var_0 ( var_1.right , var_7 )
  