code: def test_summary_xname_fe(self):
      # Test that the `xname_fe` argument is reflected in the summary table.
      summ = self.res.summary(xname_fe=["Constant", "Age", "Weight"])
      desired = ["Constant", "Age", "Weight", "Group Var"]
      actual = summ.tables[
          1
      ].index.values  # Second table is summary of params
      assert_equal(actual, desired)
  
imports: from statsmodels.compat.platform import PLATFORM_OSX
  import os
  import csv
  import warnings
  import numpy
  import pandas
  from scipy import sparse
  import pytest
  from statsmodels.regression.mixed_linear_model import MixedLM, MixedLMParams, _smw_solver, _smw_logdet
  from numpy.testing import assert_almost_equal, assert_equal, assert_allclose, assert_
  from statsmodels.base import _penalties
  import statsmodels.tools.numdiff
  from .results import lme_r_results
label_desc: Use image node_id 3 for calling the TestMixedLMSummary obj's underlying member method code with example usage: obj.test_summary_xname_fe() without return types