code: def test_proportional_hazard_test():
      """
      c = coxph(formula=Surv(T, E) ~ var1 + var2 + var3, data=df)
      cz = cox.zph(c, transform='rank')
      cz
      """
      cph = CoxPHFitter()
      df = load_regression_dataset()
      cph.fit(df, "T", "E")
      results = stats.proportional_hazard_test(cph, df)
      npt.assert_allclose(
          results.summary.loc["var1"]["test_statistic"],
          1.4938293,
          rtol=1e-3,
      )
      npt.assert_allclose(
          results.summary.loc["var2"]["test_statistic"],
          0.8792998,
          rtol=1e-3,
      )
      npt.assert_allclose(
          results.summary.loc["var3"]["test_statistic"],
          2.2686088,
          rtol=1e-3,
      )
      npt.assert_allclose(
          results.summary.loc["var3"]["p"], 0.1320184, rtol=1e-3
      )
  
imports: import numpy
  import pandas
  import numpy.testing
  import pytest
  from pandas.testing import assert_frame_equal
  from lifelines import statistics
  from lifelines import CoxPHFitter, KaplanMeierFitter, WeibullFitter
  from lifelines.exceptions import StatisticalWarning
  from lifelines.datasets import load_waltons, load_g3, load_lymphoma, load_dd, load_regression_dataset, load_leukemia
label_desc: Use image node_id 29 for calling a global function with example usage: test_proportional_hazard_test() without return types