code: def test_save_forecaster_warning_dont_save_custom_functions(
      weight_func,
  ):
      """
      Test UserWarning when custom functions are not saved.
      """
      forecaster = ForecasterAutoregMultiSeriesCustom(
          regressor=LinearRegression(),
          fun_predictors=create_predictors,
          window_size=3,
          weight_func=weight_func,
      )
  
      warn_msg = re.escape(
          (
              "Custom functions used to create predictors or weights are not saved. "
              "To save them, set `save_custom_functions` to `True`."
          )
      )
      with pytest.warns(UserWarning, match=warn_msg):
          save_forecaster(
              forecaster=forecaster,
              file_name="forecaster.joblib",
              save_custom_functions=False,
          )
          os.remove("forecaster.joblib")
  
imports: import os
  import re
  import joblib
  import pytest
  import inspect
  import warnings
  import numpy
  import pandas
  import skforecast
  from skforecast.ForecasterAutoreg import ForecasterAutoreg
  from skforecast.ForecasterAutoregMultiSeriesCustom import ForecasterAutoregMultiSeriesCustom
  from skforecast.utils import save_forecaster
  from skforecast.utils import load_forecaster
  from skforecast.exceptions import SkforecastVersionWarning
  from sklearn.linear_model import LinearRegression
label_desc: Use image node_id 7 for calling a global function with example usage: test_save_forecaster_warning_dont_save_custom_functions(weight_func) without return types