code: def exampletest(res_armarep):
      from statsmodels.sandbox import tsa
  
      arrep = tsa.arma_impulse_response(
          res_armarep.ma, res_armarep.ar, nobs=21
      )[1:]
      marep = tsa.arma_impulse_response(
          res_armarep.ar, res_armarep.ma, nobs=21
      )[1:]
      assert_array_almost_equal(res_armarep.marep.ravel(), marep, 14)
      # difference in sign convention to matlab for AR term
      assert_array_almost_equal(-res_armarep.arrep.ravel(), arrep, 14)
  
file_path: statsmodels/statsmodels/sandbox/tests/maketests_mlabwrap.py
imports: import numpy
  from numpy.testing import assert_array_almost_equal
  from numpy import array
label_desc: Use image node_id 3 for calling a global function with example usage: exampletest(res_armarep) without return types