code: def test_score_function_null(daily_data):
      """Tests fit and its compatibility with predict/score.
      Checks score function accuracy with null model
      """
      model = SimpleSilverkiteEstimator(
          null_model_params={"strategy": "mean"},
          fit_algorithm_dict={"fit_algorithm": "linear"},
          holidays_to_model_separately=[],
          yearly_seasonality=5,
          quarterly_seasonality=False,
          monthly_seasonality=False,
          weekly_seasonality=3,
          feature_sets_enabled=False,
      )
      train_df = daily_data["train_df"]
  
      model.fit(
          train_df, time_col=cst.TIME_COL, value_col=cst.VALUE_COL
      )
      assert model.fit_algorithm_dict == {
          "fit_algorithm": "linear",
          "fit_algorithm_params": None,
      }
      score = model.score(
          daily_data["test_df"], daily_data["test_df"][cst.VALUE_COL]
      )
      assert score == pytest.approx(0.90, rel=1e-2)
  
imports: import datetime
  import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
  from sklearn.linear_model import SGDRegressor
  from sklearn.metrics import mean_squared_error
  import greykite.common.constants
  from greykite.algo.forecast.silverkite.forecast_simple_silverkite import SimpleSilverkiteForecast
  from greykite.common.constants import EVENT_DF_DATE_COL
  from greykite.common.constants import EVENT_DF_LABEL_COL
  from greykite.common.data_loader import DataLoader
  from greykite.common.features.timeseries_features import convert_date_to_continuous_time
  from greykite.common.python_utils import assert_equal
  from greykite.common.testing_utils import daily_data_reg
  from greykite.common.testing_utils import generate_df_for_tests
  from greykite.common.testing_utils import generate_df_with_reg_for_tests
  from greykite.sklearn.estimator.simple_silverkite_estimator import SimpleSilverkiteEstimator
  from greykite.sklearn.estimator.testing_utils import params_component_breakdowns
label_desc: Use image node_id 9 for calling a global function with example usage: test_score_function_null(daily_data) without return types