class_docstr: The Tuning objective for HPO.
code: def _post_train(self, model):
      if self.mode == "best":
          self.searcher.trainer.callbacks.pop()
  
imports: from collections import namedtuple
  from typing import Optional, Union
  import pytorch_lightning
  from pytorch_lightning.utilities.types import EVAL_DATALOADERS, TRAIN_DATALOADERS
  from pytorch_lightning.utilities import rank_zero_deprecation
  from pytorch_lightning.core.datamodule import LightningDataModule
  from bigdl.nano.pytorch import InferenceOptimizer
  from bigdl.nano.automl.hpo.backend import create_pl_pruning_callback
  from bigdl.nano.utils.common import invalidInputError
  from ._helper import LatencyCallback, _remove_metric_prefix, BestMetricCallback
  import inspect
  import copy
label_desc: Use image node_id 4 for calling the Objective obj's underlying member method code with example usage: obj._post_train(model) without return types