code: def test_dfm(missing=None):
      mod = dynamic_factor.DynamicFactor(
          dta, k_factors=2, factor_order=1
      )
      mod.update(mod.start_params)
      sim_cfa = mod.simulation_smoother(method="cfa")
      res = mod.ssm.smooth()
  
      # Test zero variates
      sim_cfa.simulate(np.zeros((mod.k_states, mod.nobs)))
      assert_allclose(sim_cfa.simulated_state, res.smoothed_state)
  
imports: import os
  import numpy
  from numpy.testing import assert_allclose
  import pandas
  from scipy.linalg import cho_solve_banded
  from statsmodels import datasets
  from statsmodels.tsa.statespace import sarimax, structural, dynamic_factor, varmax
label_desc: Use image node_id 1 for calling a global function with example usage: test_dfm(missing) without return types