comefrom: <doocs>0501.Find Mode in Binary Search Tree_1.py
code: def dfs(root):
      if root is None:
          return
      nonlocal mx, prev, ans, cnt
      dfs(root.left)
      cnt = cnt + 1 if prev == root.val else 1
      if cnt > mx:
          ans = [root.val]
          mx = cnt
      elif cnt == mx:
          ans.append(root.val)
      prev = root.val
      dfs(root.right)
masked: def sample_funcname ( var_1 ) :
      if var_1 is None :
          return
      nonlocal var_3 , var_4 , var_5 , var_6
      var_0 ( var_1.left )
      var_6 = var_6 + 1 if var_4 == var_1.val else 1
      if var_6 > var_3 :
          var_5 = [ var_1.val ]
          var_3 = var_6
      elif var_6 == var_3 :
          var_5.append ( var_1.val )
      var_4 = var_1.val
      var_0 ( var_1.right )
  