code: def test_depth_sum(self):
      self.assertEqual(253, depth_sum(self.tree.root, 4))
  
file_path: keon-algos/algorithms/tree/bst/depth_sum.py
imports: import unittest
  from bst import Node
  from bst import bst
label_desc: Use image node_id 2 for calling the TestSuite obj's underlying member method code with example usage: obj.test_depth_sum() without return types