code: def test_time_varying_state_cov(reset_randomstate):
      mod = TVSS(np.zeros((10, 2)))
      mod["obs_cov"] = mod["obs_cov", :, :, 0] * 0
      mod["selection"] = mod["selection", :, :, 0]
      mod["state_intercept", :] = 0
      mod["state_cov"] = np.zeros(
          (mod.ssm.k_posdef, mod.ssm.k_posdef, mod.nobs)
      )
      mod["state_cov", ..., -1] = np.eye(mod.ssm.k_posdef)
      assert_equal(mod["obs_cov"].shape, (mod.k_endog, mod.k_endog))
      assert_equal(
          mod["selection"].shape, (mod.k_states, mod.ssm.k_posdef)
      )
      sim = mod.simulate([], 10)
      assert_allclose(sim, mod["obs_intercept"].T)
  
imports: from statsmodels.compat.pandas import MONTH_END
  import numpy
  from numpy.testing import assert_, assert_allclose, assert_equal
  import pandas
  import pytest
  from scipy.signal import lfilter
  from statsmodels.tools.sm_exceptions import EstimationWarning, SpecificationWarning
  from statsmodels.tsa.statespace import dynamic_factor, sarimax, structural, varmax
  from .test_impulse_responses import TVSS
label_desc: Use image node_id 45 for calling a global function with example usage: test_time_varying_state_cov(reset_randomstate) without return types