docstr: restore the forecaster.
  
  :param checkpoint_file: The checkpoint file location you want to load the forecaster.
docstr_tok: ["restore","the","forecaster",".",":","param","checkpoint_file",":","The","checkpoint","file","location","you","want","to","load","the","forecaster","."]
code: def load(self, checkpoint_file):
      """
      restore the forecaster.
  
      :param checkpoint_file: The checkpoint file location you want to load the forecaster.
      """
      self.trainer = Trainer(
          logger=False,
          max_epochs=1,
          checkpoint_callback=self.checkpoint_callback,
          num_processes=1,
          use_ipex=self.use_ipex,
          distributed_backend="spawn",
      )
      checkpoint = torch.load(checkpoint_file)
      config = checkpoint["hyper_parameters"]
      args = _transform_config_to_namedtuple(config)
      internal = AutoFormer.load_from_checkpoint(
          checkpoint_file, configs=args
      )
      self.internal = internal
  
imports: import torch
  import numpy
  from pandas import Timedelta
  from bigdl.chronos.forecaster.abstract import Forecaster
  from bigdl.chronos.forecaster.utils import read_csv, delete_folder
  from bigdl.chronos.metric.forecast_metrics import Evaluator
  from bigdl.chronos.model.autoformer import model_creator, loss_creator
  from torch.utils.data import TensorDataset, DataLoader
  from bigdl.chronos.model.autoformer.Autoformer import AutoFormer, _transform_config_to_namedtuple
  from bigdl.nano.utils.common import invalidInputError, invalidOperationError
  from bigdl.chronos.forecaster.utils import check_transformer_data
  from bigdl.chronos.pytorch import TSTrainer
  from bigdl.chronos.data import TSDataset
  from bigdl.nano.automl.hpo.space import Space
  from bigdl.chronos.forecaster.utils_hpo import GenericTSTransformerLightningModule, _config_has_search_space
  from bigdl.chronos.pytorch.context_manager import DummyForecasterContextManager, ForecasterContextManager
  from .utils_hpo import _format_metric_str
  import warnings
  from tempfile import TemporaryDirectory
  import os
label_desc: Use image node_id 11 for calling the AutoformerForecaster obj's underlying member method code with example usage: obj.load(checkpoint_file) without return types