code: def test_count_left_node(self):
      self.assertEqual(4, count_left_node(self.tree.root))
  
file_path: keon-algos/algorithms/tree/bst/count_left_node.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_count_left_node() without return types