code: def test_fit_last_window_stored():
      """
      Test that values of last window are stored after fitting.
      """
      series = pd.DataFrame(
          {"1": pd.Series(np.arange(5)), "2": pd.Series(np.arange(5))}
      )
  
      forecaster = ForecasterAutoregMultiSeriesCustom(
          regressor=LinearRegression(),
          fun_predictors=create_predictors,
          window_size=3,
      )
      forecaster.fit(series=series)
      expected = pd.DataFrame(
          {
              "1": pd.Series(np.array([2, 3, 4])),
              "2": pd.Series(np.array([2, 3, 4])),
          }
      )
      expected.index = pd.RangeIndex(start=2, stop=5, step=1)
  
      pd.testing.assert_frame_equal(forecaster.last_window, expected)
  
file_path: skforecast/skforecast/ForecasterAutoregMultiSeriesCustom/tests/test_fit.py
imports: import re
  import pytest
  import numpy
  import pandas
  from skforecast.ForecasterAutoregMultiSeriesCustom import ForecasterAutoregMultiSeriesCustom
  from sklearn.linear_model import LinearRegression
  from sklearn.preprocessing import StandardScaler
label_desc: Use image node_id 9 for calling a global function with example usage: test_fit_last_window_stored() without return types