code: def test_set_jump_existing_trial(self):
      lineages = Lineages()
      root_1 = TrialStub(id="root-1")
      lineage_1 = lineages.add(root_1)
      root_2 = TrialStub(id="root-2")
      lineage_2 = lineages.add(root_2)
      child_trial = TrialStub(id="child")
      child_lineage = lineages.fork(root_1, child_trial)
      lineages.set_jump(root_2, child_trial)
  
      assert child_lineage.base is lineage_2
      assert lineage_2.jumps == [child_lineage]
      assert child_lineage.jumps == []
      assert lineage_2.base is None
      assert lineage_1.jumps == []
      assert lineage_1.base is None
  
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 8 for calling the TestLineages obj's underlying member method code with example usage: obj.test_set_jump_existing_trial() without return types