code: def test_simple_implementation(self):
      predicate = MagicMock()
      child_opr = LogicalGet(MagicMock(), MagicMock(), MagicMock())
      root_opr = LogicalFilter(predicate, [child_opr])
  
      opt_cxt, root_grp_id = self.top_down_rewrite(root_opr)
      opt_cxt, root_grp_id = self.bottom_up_rewrite(
          root_grp_id, opt_cxt
      )
      opt_cxt, root_grp_id = self.implement_group(root_grp_id, opt_cxt)
  
      root_grp = opt_cxt.memo.groups[root_grp_id]
      best_root_grp_expr = root_grp.get_best_expr(PropertyType.DEFAULT)
  
      self.assertEqual(type(best_root_grp_expr.opr), PredicatePlan)
  
imports: import unittest
  from unittest.mock import patch
  from mock import MagicMock
  from evadb.optimizer.cost_model import CostModel
  from evadb.optimizer.operators import LogicalFilter, LogicalGet, LogicalProject, LogicalQueryDerivedGet
  from evadb.optimizer.optimizer_context import OptimizerContext
  from evadb.optimizer.optimizer_tasks import BottomUpRewrite, OptimizeGroup, OptimizerTask, TopDownRewrite
  from evadb.optimizer.property import PropertyType
  from evadb.optimizer.rules.rules_manager import RulesManager
  from evadb.plan_nodes.predicate_plan import PredicatePlan
  from evadb.plan_nodes.project_plan import ProjectPlan
  from evadb.plan_nodes.seq_scan_plan import SeqScanPlan
label_desc: Use image node_id 6 for calling the TestOptimizerTask obj's underlying member method code with example usage: obj.test_simple_implementation() without return types