code: def test_start_params():
      endog = lake.copy()
  
      # Test for valid use of starting parameters
      p, _ = statespace(
          endog, order=(1, 0, 0), start_params=[0, 0, 1.0]
      )
      p, _ = statespace(
          endog,
          order=(1, 0, 0),
          start_params=[0, 1.0, 1.0],
          enforce_stationarity=False,
      )
      p, _ = statespace(
          endog,
          order=(0, 0, 1),
          start_params=[0, 1.0, 1.0],
          enforce_invertibility=False,
      )
  
      # Test for invalid use of starting parameters
      assert_raises(
          ValueError,
          statespace,
          endog,
          order=(1, 0, 0),
          start_params=[0, 1.0, 1.0],
      )
      assert_raises(
          ValueError,
          statespace,
          endog,
          order=(0, 0, 1),
          start_params=[0, 1.0, 1.0],
      )
  
file_path: statsmodels/statsmodels/tsa/arima/estimators/tests/test_statespace.py
imports: import numpy
  from numpy.testing import assert_allclose, assert_raises
  from statsmodels.tools.tools import add_constant
  from statsmodels.tsa.statespace import sarimax
  from statsmodels.tsa.arima.datasets.brockwell_davis_2002 import lake
  from statsmodels.tsa.arima.estimators.statespace import statespace
label_desc: Use image node_id 2 for calling a global function with example usage: test_start_params() without return types