docstr: Historical forecast can be optimized only if `retrain=False` and `forecast_horizon <= model.output_chunk_length`
  (no auto-regression required).
docstr_tok: ["Historical","forecast","can","be","optimized","only","if","`","retrain=False","`","and","`","forecast_horizon","<","=","model.output_chunk_length","`","(","no","auto-regression","required",")","."]
code: def _check_optimizable_historical_forecasts(
      self,
      forecast_horizon: int,
      retrain: Union[bool, int, Callable[..., bool]],
      show_warnings: bool,
  ) -> bool:
      """
      Historical forecast can be optimized only if `retrain=False` and `forecast_horizon <= model.output_chunk_length`
      (no auto-regression required).
      """
      return _check_optimizable_historical_forecasts_global_models(
          model=self,
          forecast_horizon=forecast_horizon,
          retrain=retrain,
          show_warnings=show_warnings,
          allow_autoregression=False,
      )
  
imports: from collections import OrderedDict
  from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple, Union
  import numpy
  import pandas
  from sklearn.linear_model import LinearRegression
  from darts.logging import get_logger, raise_if, raise_if_not, raise_log
  from darts.models.forecasting.forecasting_model import GlobalForecastingModel
  from darts.timeseries import TimeSeries
  from darts.utils.data.tabularization import add_static_covariates_to_lagged_data, create_lagged_component_names, create_lagged_training_data
  from darts.utils.historical_forecasts import _check_optimizable_historical_forecasts_global_models, _optimized_historical_forecasts_all_points, _optimized_historical_forecasts_last_points_only, _process_historical_forecast_input
  from darts.utils.multioutput import MultiOutputRegressor
  from darts.utils.utils import _check_quantiles, get_single_series, seq2series, series2seq
label_desc: Use image node_id 21 for calling the RegressionModel obj's underlying member method code with example usage: obj._check_optimizable_historical_forecasts(forecast_horizon, retrain, show_warnings) and returns: _check_optimizable_historical_forecasts_global_models