code: def test_log_rank_test_on_waltons_dataset():
      df = load_waltons()
      ix = df["group"] == "miR-137"
      waltonT1 = df.loc[ix]["T"]
      waltonT2 = df.loc[~ix]["T"]
      result = stats.logrank_test(waltonT1, waltonT2)
      assert result.p_value < 0.05
  
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 18 for calling a global function with example usage: test_log_rank_test_on_waltons_dataset() without return types