code: def test_initialization_known(austourists):
      initial_level, initial_trend = [36.46466837, 34.72584983]
      model = ETSModel(
          austourists,
          error="add",
          trend="add",
          damped_trend=True,
          initialization_method="known",
          initial_level=initial_level,
          initial_trend=initial_trend,
      )
      internal_params = model._internal_params(model._start_params)
      assert initial_level == internal_params[4]
      assert initial_trend == internal_params[5]
      assert internal_params[6] == 0
  
imports: from statsmodels.compat.pandas import QUARTER_END
  from statsmodels.compat.platform import PLATFORM_LINUX32, PLATFORM_WIN
  from itertools import product
  import json
  import pathlib
  import numpy
  from numpy.testing import assert_allclose, assert_almost_equal
  import pandas
  import pytest
  import scipy.stats
  from statsmodels.tsa.exponential_smoothing.ets import ETSModel
  import statsmodels.tsa.holtwinters
  import statsmodels.tsa.statespace.exponential_smoothing
label_desc: Use image node_id 23 for calling a global function with example usage: test_initialization_known(austourists) without return types