code: def test_set_up(params):
      """Tests the set up of ``MultistageForecastEstimator``."""
      # Instatiation.
      model = MultistageForecastEstimator(**params)
      assert model.model_configs == params["model_configs"]
      assert model.forecast_horizon == params["forecast_horizon"]
      assert model.freq == params["freq"]
      assert model.train_lengths is None
      assert model.fit_lengths is None
      assert model.agg_funcs is None
      assert model.agg_freqs is None
      assert model.estimators is None
      assert model.estimator_params is None
      assert model.train_lengths_in_seconds is None
      assert model.fit_lengths_in_seconds is None
      assert model.fit_lengths_in_seconds is None
      assert model.max_ar_orders is None
      assert model.data_freq_in_seconds is None
      assert model.num_points_per_agg_freqs is None
      assert model.models is None
      assert model.fit_df is None
      assert model.train_end is None
  
      # Initialization for some derived parameters.
      model._initialize()
      assert model.train_lengths == ["30D", "7D"]
      assert model.fit_lengths == ["30D", "7D"]
      assert len(model.agg_funcs) == 2
      assert model.agg_freqs == ["D", "H"]
      assert model.estimators == [
          SimpleSilverkiteEstimator,
          SimpleSilverkiteEstimator,
      ]
      assert model.estimator_params == [
          config.estimator_params for config in params["model_configs"]
      ]
      assert model.train_lengths_in_seconds == [
          60 * 60 * 24 * 30,
          60 * 60 * 24 * 7,
      ]
      assert model.fit_lengths_in_seconds == [
          60 * 60 * 24 * 30,
          60 * 60 * 24 * 7,
      ]
      assert len(model.models) == 2
      assert model.data_freq_in_seconds == 60 * 60
  
imports: import datetime
  import numpy
  import pandas
  import pytest
  from testfixtures import LogCapture
  import greykite.common.constants
  from greykite.common.testing_utils import generate_df_for_tests
  from greykite.sklearn.estimator.lag_based_estimator import LagBasedEstimator
  from greykite.sklearn.estimator.multistage_forecast_estimator import MultistageForecastEstimator
  from greykite.sklearn.estimator.multistage_forecast_estimator import MultistageForecastModelConfig
  from greykite.sklearn.estimator.simple_silverkite_estimator import SimpleSilverkiteEstimator
  from greykite.sklearn.uncertainty.uncertainty_methods import UncertaintyMethodEnum
label_desc: Use image node_id 8 for calling a global function with example usage: test_set_up(params) without return types