code: def recur_depth_sum(root, n):
      if root is None:
          return 0
      elif root.left is None and root.right is None:
          return root.data * n
      else:
          return (
              n * root.data
              + recur_depth_sum(root.left, n + 1)
              + recur_depth_sum(root.right, n + 1)
          )
  
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 a global function with example usage: recur_depth_sum(root, n) and returns: int, unknown, unknown