code: def test_fit(self):
      np.random.seed(42)
      llh_noexog = TwoPeakLLHNoExog(
          self.X, signal=self.pdf_a, background=self.pdf_b
      )
  
      res = llh_noexog.fit()
      assert_allclose(res.params, self.params, rtol=1e-1)
      # TODO: nan if exog is None,
      assert res.df_resid == 248
      assert res.df_model == 0
      res_bs = res.bootstrap(nrep=50)
      assert_allclose(res_bs[2].mean(0), self.params, rtol=1e-1)
      # SMOKE test,
      res.summary()
  
imports: import numpy
  from scipy import stats
  from statsmodels.base.model import GenericLikelihoodModel
  from numpy.testing import assert_array_less, assert_almost_equal, assert_allclose
label_desc: Use image node_id 2 for calling the TestTwoPeakLLHNoExog obj's underlying member method code with example usage: obj.test_fit() without return types