code: def test_get_best_trial_broken_leaf(self):
      root = build_full_tree(4, starting_objective=1)
  
      leafs = root.get_nodes_at_depth(3)
      leafs[0].item.objective = None
      assert leafs[0].get_best_trial() == root.item
  
imports: import os
  import random
  import pytest
  from base import ObjectiveStub, TrialStub, build_full_tree, build_population, compare_generations
  from orion.algo.pbt.pbt import LineageNode, Lineages
label_desc: Use image node_id 13 for calling the TestLineageNode obj's underlying member method code with example usage: obj.test_get_best_trial_broken_leaf() without return types