code: def test_name_ci_vector(data):
      if not isinstance(data, pd.DataFrame):
          return
      eg = engle_granger(data.w, data[["x", "y", "z"]])
      ci = eg.cointegrating_vector
      assert list(ci.index) == ["w", "x", "y", "z", "const"]
  
file_path: arch/arch/tests/unitroot/test_engle_granger.py
imports: import numpy
  from numpy.testing import assert_allclose
  import pandas
  import pytest
  from statsmodels.iolib.summary import Summary
  from arch.unitroot._engle_granger import engle_granger_cv, engle_granger_pval
  from arch.unitroot._shared import ResidualCointegrationTestResult, _cross_section
  from arch.unitroot.cointegration import engle_granger
label_desc: Use image node_id 9 for calling a global function with example usage: test_name_ci_vector(data) without return types