code: def test_errors(df, forecast_config):
      # No configs with MULTISTAGE_EMPTY.
      template = MultistageForecastTemplate()
      template.df = df
      forecast_config.model_components_param.custom[
          "multistage_forecast_configs"
      ] = None
      forecast_config.model_template = "MULTISTAGE_EMPTY"
      template.config = forecast_config
      with pytest.raises(
          ValueError,
          match="``MULTISTAGE_EMPTY`` can not be used without over",
      ):
          template.get_hyperparameter_grid()
  
      # The config has wrong type.
      template = MultistageForecastTemplate()
      template.df = df
      forecast_config.model_components_param.custom[
          "multistage_forecast_configs"
      ] = 5
      forecast_config.model_template = "SILVERKITE_TWO_STAGE"
      template.config = forecast_config
      with pytest.raises(
          ValueError,
          match="The ``multistage_forecast_configs`` parameter must be a list of",
      ):
          template.get_hyperparameter_grid()
  
imports: import datetime
  import numpy
  import pytest
  from testfixtures import LogCapture
  from greykite.common.constants import LOGGER_NAME
  from greykite.common.constants import PREDICTED_COL
  from greykite.common.constants import PREDICTED_LOWER_COL
  from greykite.common.constants import PREDICTED_UPPER_COL
  from greykite.common.constants import TIME_COL
  from greykite.common.constants import VALUE_COL
  from greykite.common.testing_utils import generate_df_for_tests
  from greykite.framework.templates.autogen.forecast_config import EvaluationPeriodParam
  from greykite.framework.templates.autogen.forecast_config import ForecastConfig
  from greykite.framework.templates.autogen.forecast_config import MetadataParam
  from greykite.framework.templates.autogen.forecast_config import ModelComponentsParam
  from greykite.framework.templates.forecaster import Forecaster
  from greykite.framework.templates.multistage_forecast_template import MultistageForecastTemplate
  from greykite.framework.templates.multistage_forecast_template_config import SILVERKITE_TWO_STAGE
  from greykite.framework.templates.multistage_forecast_template_config import MultistageForecastTemplateConfig
  from greykite.framework.templates.simple_silverkite_template import SimpleSilverkiteTemplate
  from greykite.sklearn.estimator.simple_silverkite_estimator import SimpleSilverkiteEstimator
  from greykite.sklearn.uncertainty.uncertainty_methods import UncertaintyMethodEnum
label_desc: Use image node_id 17 for calling a global function with example usage: test_errors(df, forecast_config) without return types