code: def test_get_fitted_params_sklearn():
      """Tests fitted parameter retrieval with sklearn components.
  
      Raises
      ------
      AssertionError if logic behind get_fitted_params is incorrect, logic tested:
          calling get_fitted_params on obj sktime component returns expected nested params
      """
      from sktime.datasets import load_airline
      from sktime.forecasting.trend import TrendForecaster
  
      y = load_airline()
      f = TrendForecaster().fit(y)
  
      params = f.get_fitted_params()
  
      assert "regressor__coef" in params.keys()
      assert "regressor" in params.keys()
      assert "regressor__intercept" in params.keys()
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_get_fitted_params_sklearn() without return types