new_contents: # Definition for a  binary tree node
  # class TreeNode:
  #     def __init__(self, x):
  #         self.val = x
  #         self.left = None
  #         self.right = None
  
  
  class Solution:
      # @param root, a tree node
      # @return a list of integers
  
      def rightSideView(self, root):
          res = []
  
          def dfs(root, level):
              if not root:
                  return
              if len(res) == level:
                  res.append(root.val)
              dfs(root.right, level+1)
              dfs(root.left, level+1)
  
          dfs(root, 0)
          return res
  
subject: add solution for Binary Tree Right Side View